Method and apparatus for transmitting control information

ABSTRACT

A method is described for transmitting uplink control information at a communication apparatus configured with a plurality of cells including a Primary Cell (PCell) and a Secondary Cell (SCell) in a wireless communication system operating in a Time Division Duplex (TDD) mode. One or more downlink signals requiring Hybrid Automatic Repeat reQuest Acknowledgement (HARQ-ACK) feedback are received in a set of subframes. Reception response information about the one or more downlink signals is transmitted through a Physical Uplink Control CHannel (PUCCH) on a subframe configured for Scheduling Request (SR) transmission. When a predetermined condition is not satisfied, the reception response information and SR information are multiplexed and transmitted using a first HARQ-ACK PUCCH resource. When the predetermined condition is satisfied, for a positive SR, the reception response information includes information about an ACK count for the one or more downlink signals and is transmitted using a SR PUCCH resource.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is continuation of co-pending U.S. application Ser. No.13/806,623 filed on Dec. 21, 2012 (now U.S. Pat. No. 8,995,313 issued onMar. 31, 2015), which is the National Phase of PCT/KR2011/006909 filedon Sep. 19, 2011, which claims priority under 35 U.S.C. 119(e) to U.S.Provisional Application No. 61/384,300 filed on Sep. 19, 2010; U.S.Provisional Application No. 61/389,693 filed on Oct. 4, 2010; U.S.Provisional Application No. 61/409,956 filed on Nov. 3, 2010; U.S.Provisional Application No. 61/417,282 filed on Nov. 26, 2010 and U.S.Provisional Application No. 61/436,596 filed on Jan. 26, 2011. Thecontents of all of these applications are hereby incorporated byreference as fully set forth herein in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a wireless communication system and,most particularly, to a method and apparatus for transmitting controlinformation.

Discussion of the Related Art

Wireless communication systems are being broadly developed in order toprovide various types of communication services, such as voice or dataservices. Generally, a wireless communication system corresponds to amultiple access system that may support communication with multipleusers by sharing an available system source (bandwidth, transmissionpower, and so on). Examples of a multiple access system include a CDMA(code division multiple access) system, an FDMA (frequency divisionmultiple access) system, a TDMA (time division multiple access) system,an OFDMA (orthogonal frequency division multiple access) system, anSC-FDMA (single carrier frequency division multiple access) system, andso on.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method and apparatusfor efficiently transmitting control information in a wirelesscommunication system. Another object of the present invention is toprovide a method and apparatus for efficiently transmitting uplinkcontrol information in a multi-cell situation and efficiently managingresources for the uplink control information transmission. It is to beunderstood that objects to be achieved by the present invention are notlimited to the aforementioned objects and other objects which are notmentioned will be apparent to those of ordinary skill in the art towhich the present invention pertains from the following description.

According to an aspect of the present invention, the object of thepresent invention can be achieved by providing transmitting uplinkcontrol information at a communication apparatus configured with aplurality of cells including a Primary Cell (PCell) and a Secondary Cell(SCell) in a wireless communication system, the method comprising:receiving at least one of one or more Physical Downlink Control CHannels(PDCCHs) and one or more Physical Downlink Shared CHannels (PDSCHs);generating reception response information about the at least one of theone or more PDCCHs and the one or more PDSCHs; and transmitting thereception response information through a Physical Uplink Control CHannel(PUCCH) on a Scheduling Request (SR) subframe, wherein the receptionresponse information and SR information are multiplexed and transmittedusing a PUCCH resource for Hybrid Automatic Repeat requestAcknowledgement (HARQ-ACK) when a predetermined condition is notsatisfied, and wherein the reception response information is transmittedusing a PUCCH resource for SR when the predetermined condition issatisfied, wherein the predetermined condition includes at least one ofthe following conditions: (1) a single PDSCH transmission only on thePCell indicated by detection of a PDCCH having a Downlink AssignmentIndex (DAI) initial value is present; (2) a single PDCCH transmissiononly on the PCell that has the DAI initial value and indicates aSemi-Persistent Scheduling (SPS) release is present; and (3) a singlePDSCH transmission only on the PCell where there is not a correspondingPDCCH.

According to another aspect of the present invention, the object of thepresent invention can be achieved by providing a communication apparatusconfigured to transmit uplink control information in a situation that aplurality of cells including a PCell and an SCell are configured in awireless communication system, the communication apparatus comprising: aRadio Frequency (RF) unit; and a processor configured to receive atleast one of one or more Physical Downlink Control CHannels (PDCCHs) andone or more Physical Downlink Shared CHannels (PDSCHs), to generatereception response information about the at least one of the one or morePDCCHs and the one or more PDSCHs, and to transmit the receptionresponse information through a Physical Uplink Control CHannel (PUCCH)on a Scheduling Request (SR) subframe, wherein the reception responseinformation and SR information are multiplexed and transmitted using aPUCCH resource for Hybrid Automatic Repeat request Acknowledgement(HARQ-ACK) when a predetermined condition is not satisfied, and whereinthe reception response information is transmitted using a PUCCH resourcefor SR when the predetermined condition is satisfied, wherein thepredetermined condition includes at least one of the followingconditions: (1) a single PDSCH transmission designated by detection of aPDCCH having a Downlink Assignment Index (DAI) initial value is presenton the PCell only; (2) a single PDCCH transmission that has the DAIinitial value and indicates a Semi-Persistent Scheduling (SPS) releaseis present on the PCell only; and (3) a single PDSCH transmissionwithout a corresponding PDCCH is present on the PCell only.

The DAI initial value may be 1.

When the predetermined condition is satisfied, information about an ACKcount for the at least one of the one or more PDCCHs and the one or morePDSCHs may be transmitted using the PUCCH resource for SR.

The ACK count may be set to 0 when the reception response informationabout the at least one of the one or more PDCCHs and the one or morePDSCHs includes Negative Acknowledgement (NACK) or DiscontinuousTransmission (DTX).

1-bit information indicating a positive/negative SR may be added to thereception response information when the predetermined condition is notsatisfied.

The PUCCH for HARQ-ACK may be indicated by Transmit Power Control (TPC)field values of one or more SCell PDCCHs and/or one or more PCell PDCCHsthat do not correspond to the DAI initial value when the predeterminedcondition is not satisfied.

The communication apparatus may be configured with a Time DivisionDuplex (TDD) mode.

In accordance with the present invention, control information can beefficiently transmitted in a wireless communication system.Specifically, uplink control information can be efficiently transmittedin an environment having a plurality of cells, and resources for theuplink control information transmission can be efficiently managed

The effects that may be gained from the embodiment of the presentinvention will not be limited only to the effects described above.Accordingly, other effects of the present application, which are notmentioned herein, will become apparent to those having ordinary skill inthe art.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the technical principleof the invention.

FIG. 1 illustrates physical channels that are used in a 3GPP LTE system,which corresponds to an exemplary wireless communication system, and ageneral signal transmitting method using the physical channels.

FIG. 2A illustrates an exemplary structure of a radio frame.

FIG. 2B illustrates an exemplary resource grid of a downlink slot.

FIG. 3 illustrates a structure of a downlink frame.

FIG. 4 illustrates a structure of an uplink subframe.

FIG. 5 illustrates an exemplary procedure of physically mapping a PUCCHformat to a PUCCH domain.

FIG. 6 illustrates a slot level structure of PUCCH formats 2/2a/2b.

FIG. 7 illustrates a slot level structure of PUCCH formats 1a/1b.

FIG. 8 illustrates an example of deciding a PUCCH resource for ACK/NACK.

FIG. 9 illustrates an exemplary method of multiplexing an ACK/NACK withan SR.

FIG. 10 illustrates an exemplary Carrier Aggregation (CA) communicationsystem.

FIG. 11 illustrates an exemplary cross-carrier scheduling.

FIGS. 12˜13 illustrate an exemplary E-PUCCH format based onblock-spreading (or block-dispersion).

FIG. 14 illustrates exemplary operations of a base station and a userequipment in a DL CC modification section.

FIG. 15 illustrates an exemplary ACK/NACK channel selection methodaccording to the conventional LTE.

FIG. 16 illustrates an exemplary ACK/NACK transmitting method accordingto a PCC fallback method.

FIG. 17 illustrates an exemplary UCI transmitting method according to anembodiment of the present invention.

FIG. 18 illustrates a bundled ACK/NACK transmitting method according toan embodiment of the present invention.

FIG. 19 illustrates an exemplary UCI transmitting method according toanother embodiment of the present invention.

FIG. 20 illustrates an exemplary UCI transmitting method according toyet another embodiment of the present invention.

FIG. 21 illustrates an exemplary UCI transmitting method according toyet another embodiment of the present invention.

FIG. 22 illustrates an exemplary base station and an exemplary userequipment that can be applied to the embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The technology described below may be used in a wide range of wirelessaccess systems, such as CDMA (Code Division Multiple Access), FDMA(Frequency Division Multiple Access), TDMA (Time Division MultipleAccess), OFDMA (Orthogonal Frequency Division Multiple Access), SC-FDMA(Single Carrier Frequency Division Multiple Access), and so on. Herein,the CDMA may be realized by a radio technology such as UTRA (UniversalTerrestrial Radio Access) or CDMA2000. The TDMA may be realized by aradio technology such as GSM (Global System for Mobilecommunications)/GPRS (General Packet Radio Service)/EDGE (Enhanced DataRates for GSM Evolution). The OFDMA may be realized by a radiotechnology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802-20, E-UTRA (Evolved UTRA), and so on. The UTRA corresponds to aportion of the UMTS (Universal Mobile Telecommunications System). And,as a portion of the E-UMTS (Evolved UMTS) using the E-UTRA, the 3GPP(3rd Generation Partnership Project) LTE (long term evolution) systemadopts the OFDMA in a downlink and adopts the SC-FDMA in an uplink. TheLTE-A (LTE-Advanced) corresponds to an evolved version of the 3GPP LTEsystem.

For the clarity in the description of the present invention, the presentinvention will be described based upon the 3GPP LTE/LTE-A systems.Nevertheless, the scope and spirit of the present invention will not belimited only to those of the 3GPP LTE system and the 3GPP LTE-A system.Additionally, the specific terms used in the following description ofthe present invention are provided to facilitate the understanding ofthe present invention. And, therefore, without deviating from thetechnical scope and spirit of the present invention, such specific termsmay also be varied and/or replaced by other terms.

In a wireless communication system, a user equipment may receiveinformation from a base station via downlink (DL), and the userequipment may also transmit information via uplink (UL). The informationreceived and/or transmitted (or transceived) by the user equipmentincludes data and diverse control information. And, various physicalchannels may exist depending upon the type and purpose of theinformation received and/or transmitted (or transceived) by the userequipment.

FIG. 1 illustrates physical channels that are used in a 3GPP LTE and ageneral signal transmitting method using the same.

When a power of a user equipment is turned off and then turned back on,or when a user equipment newly enters (or accesses) a cell, the userequipment performs an initial cell search process, such as synchronizingitself with the base station in step S101. For this, the user equipmentmay receive a Primary Synchronization Channel (P-SCH) and a SecondarySynchronization Channel (S-SCH) from the base station so as to be insynchronization with the base station, and the user equipment may alsoacquire information, such as cell ID. Thereafter, the user equipment mayreceive a Physical Broadcast Channel so as to acquire broadcastinformation within the cell. Meanwhile, the user equipment may receiveDownlink Reference Signal (DL RS), in the step of initial cell search,so as to verify the downlink channel status.

The user equipment that has completed the initial cell search mayreceive a PDCCH (Physical Downlink Control Channel) and a PDSCH(Physical Downlink Shared Channel) based upon the PDCCH (PhysicalDownlink Control Channel) information, in step S102, so as to acquiremore detailed system information.

Thereafter, in order to complete the access to the base station, theuser equipment may perform a Random Access Procedure, such as in stepsS103 and S106 of a later process, so as to complete the access to thebase station. In order to do so, the user equipment transmits a preamblethrough a PRACH (Physical Random Access Channel) (S103), and then theuser equipment may receive a response message respective to the randomaccess through the PDCCH and its respective PDSCH (S104). In case of acontention based random access, the user equipment may performContention Resolution Procedures, such as transmitting an additionalPhysical Random Access Channel (PRACH) (S105) and receiving a PhysicalDownlink Control Channel (PDCCH) and a Physical Downlink Shared Channel(PDSCH) corresponding to the PDCCH.

After performing the above-described procedures, the user equipment mayreceive a Physical Downlink Control Channel (PDCCH)/Physical DownlinkShared Channel (PDSCH) (S107), as a general uplink/downlink signaltransmission procedure, and may then perform PUSCH (Physical UplinkShared Channel)/PUCCH (Physical Uplink Control Channel) transmission(S108). The control information being transmitted by the user equipmentto the base station is collectively referred to as Uplink ControlInformation (UCI). The UCI may include HARQ ACK/NACK (Hybrid AutomaticRepeat and reQuest Acknowledgement/Negative-ACK), SR (SchedulingRequest), CQI (Channel Quality Indicator), PMI (Precoding MatrixIndicator), RI (Rank Indication), and so on. In the description of thepresent invention, the HARQ ACK/NACK will simply be referred to asHARQ-ACK or ACK/NACK (A/N). Herein, the HARQ-ACK includes at least oneof a positive ACK (simply referred to as ACK), a negative ACK (simplyreferred to as NACK), a DTX, and an NACK/DTX. The UCI is generallytransmitted through the PUCCH. However, when control information andtraffic data are to be transmitted at the same time, the UCI may also betransmitted through the PUSCH. Additionally, based upon a networkrequest/indication, the UCI may be aperiodically transmitted through thePUSCH.

FIG. 2A illustrates an exemplary structure of a radio frame. In acellular OFDM radio packet communication system, uplink/downlink datapacket transmission is performed in subframe units, and once subframe isdefined as a predetermined time period (or time section) includingmultiple OFDM symbols. The 3GPP LTE standard supports a Type 1 radioframe structure, which is applicable to FDD (Frequency Division Duplex),and a Type 2 radio frame structure, which is applicable to TDD (TimeDivision Duplex).

FIG. 2A(a) illustrates an exemplary structure of a type 1 radio frame. Adownlink radio (or wireless) frame is configured of 10 subframes, andone subframe is configured of 2 slots in a time domain. The timeconsumed (or taken) for one subframe to be transmitted is referred to asa TTI (transmission time interval). For example, the length of onesubframe may be equal to 1 ms, and the length of one slot may be equalto 0.5 ms. One slot includes a plurality of OFDM symbols in the timedomain and includes a plurality of Resource Blocks (RBs) in thefrequency domain. Since the 3GPP LTE system uses the OFDMA in adownlink, an OFDM symbol indicates one symbol section. The OFDM symbolmay also be referred to as an SC-FDMA symbol or a symbol section. As aresource allocation unit, a Resource Block (RB) may include a pluralityof consecutive subcarriers in one slot.

The number of OFDM symbols included in one slot may vary depending uponthe configuration of a CP (Cyclic Prefix). The CP may be divided into anextended CP and a normal CP. For example, in case the OFDM symbol isconfigured of a normal CP, the number of OFDM symbols included in oneslot may be equal to 7. And, in case the OFDM symbol is configured of anextended CP, since the length of an OFDM symbol is increased, the numberof OFDM symbols included in one slot becomes smaller than when the OFDMsymbol is configured of a normal CP. In case of the extended CP, forexample, the number of OFDM symbols included in one slot may be equal to6. In case the user equipment is moving at high speed, or in case thechannel status is unstable, the extended CP may be used in order tofurther reduce the interference between the symbols.

In case of using the normal CP, since one slot includes 7 PFDM symbols,one subframe includes 14 OFDM symbols. At this point, the first maximumof 3 OFDM symbols of each subframe are allocated to a PDCCH (physicaldownlink control channel), and the remaining OFDM symbols may beallocated to a PDSCH (physical downlink shared channel).

FIG. 2A(b) illustrates an exemplary structure of a type 2 radio frame.The type 2 radio frame consists of 2 half frames, and each half frameconsists of 5 subframes, a DwPTS (Downlink Pilot Time Slot), a GuardPeriod (GP), and an UpPTS (Uplink Pilot Time Slot). Herein, one subframeconsists of 2 slots. The DwPTS is used for initial cell search,synchronization, or channel estimation, which are performed by a userequipment. The UpPTS is used for channel estimation, which is performedby a base station, and for uplink transmission synchronization, which isperformed by the user equipment. The guard period corresponds to aperiod (or section) for eliminating interference occurring in an uplinkdue to a multiple path delay of a downlink signal between an uplink anda downlink.

The structure of the radio frame is merely exemplary. And, therefore,the number of subframes included in the radio frame or the number ofslots included in a subframe, and the number of symbols included in oneslot may be diversely varied.

FIG. 2B illustrates an exemplary resource grid of a downlink slot.

Referring to FIG. 2B, a downlink slot includes multiple OFDM symbols inthe time domain. One downlink slot may include 7(6) OFDM symbols in atime domain, and a resource block (RB) may include 12 sub-carriers inthe frequency domain. Each element within the resource grid is referredto as a Resource Element (RE). One RB includes 12×7(6) REs. N_(RB),which corresponds to the number of RBs, An N^(DL) number of resourceblocks included in a downlink slot is dependent to a downlinktransmission bandwidth. The structure of an uplink slot may be identicalto the above-described structure of the downlink slot. However, the OFDMsymbol may be replaced with the SC-FDMA symbol.

FIG. 3 illustrates an exemplary structure of a downlink frame. A maximumof 3(4) OFDM symbols located at the front portion of a first slot withinone subframe corresponds to a control region, wherein a control channelis allocated (or assigned). The remaining OFDM symbols correspond to adata region, wherein a Physical Downlink Shared Channel (PDSCH) isassigned. Examples of the downlink control channels that are being usedin the LTE system may include a Physical Control Format IndicatorChannel (PCFICH), a Physical Downlink Control Channel (PDCCH), aPhysical Hybrid automatic repeat request Indicator Channel (PHICH), andso on. The PCFICH carries information on the number of OFDM symbolsbeing transmitted from the first OFDM symbol of a subframe and beingused in the control channel transmission within the subframe. As aresponse to an uplink transmission, the PHICH may carry HARQ ACK/NACK(Hybrid Automatic Repeat request acknowledgment/negative-acknowledgment)signals.

The control information being transmitted through the PDCCH may bereferred to as DCI (Downlink Control Information). Herein, the DCI mayinclude resource allocation information for a user equipment or userequipment group and other control information. For example, the DCI mayinclude uplink/downlink scheduling information, an uplink transmission(Tx) power control command, and so on.

The PDCCH may carry a transmission format and resource allocationinformation of a downlink shared channel (DL-SCH), a transmission formatand resource allocation information of an uplink shared channel(UL-SCH), paging information of a paging channel (PCH), systeminformation of the DL-SCH, resource allocation information of ahigher-layer control message, such as a Random Access Response beingtransmitted over the PDSCH, a set of Tx power control commands onindividual user equipments within the user equipment group, a Tx powercontrol command, indication information on the activation of a VoIP(Voice over IP), and so on. A plurality of PDCCHs may be transmittedwithin the control region. And, the user equipment may monitor theplurality of PDCCHs. Herein, the PDCCH may be transmitted in the form ofan aggregation of one or more consecutive Control Channel Elements(CCEs). A CCE corresponds to a logical allocation unit, which is usedfor providing a coding rate to a PDCCH based on a radio (or wireless)channel state. Herein, the CCR corresponds to multiple resource elementgroups (REGs). Herein, the number of PDCCH formats and the number ofavailable data bits may be decided in accordance with the number ofCCEs. The base station may decide a PDCCH format in accordance with theDCI, which is to be transmitted to the user equipment, and may add a CRC(Cyclic Redundancy Check) to the control information. Depending upon theowner of the PDCCH or the usage purpose of the PDCCH, the CRC may bemasked with an identifier (e.g., an RNTI (Radio Network TemporaryIdentifier). For example, if the PDCCH is designated to a particular (orspecific) user equipment, an identifier (e.g., cell-RNTI (C-RNTI)) ofthe corresponding user equipment may be masked to the CRC.Alternatively, if the PDCCH is designated to a paging message, a pagingidentifier (e.g., paging-RNTI (P-RNTI)) may be masked to the CRC. If thePDCCH is designated to system information (most particularly, to asystem information block (SIC)), an S-RNTI (system information RNTI) maybe masked to the CRC. If the PDCCH is designated to a random accessresponse, an RA-RNTI (random access-RNTI) may be masked to the CRC.

FIG. 4 illustrates an exemplary structure of an uplink subframe beingused in the LTE. Referring to FIG. 4, an uplink subframe includesmultiple (e.g., 2) slots. A slot may include different numbers ofSC-FDMA symbols based upon a CP length. In the frequency domain, anuplink subframe may be divided into a control region and a data region.The data region includes a PUSCH and is used for transmitting datasignals, such as sound. The control region includes a PUCCH and is usedfor transmitting Uplink Control Information (UCI). The PUCCH includes anRB pair, which is located at each end portion of the data region alongthe frequency axis, and may be “frequency-hopped” at the slot boundary.

The PUCCH may be used for transmitting the following controlinformation.

-   -   SR (Scheduling Request): corresponds to information that is used        for requesting uplink UL-SCH resource. The SR is transmitted by        using an OOK (On-Off Keying) method.    -   HARQ-ACK/NACK: corresponds to a response signal for a downlink        data packet within the PDSCH. The HARQ-ACK/NACK indicates        whether or not the downlink data packet has been successfully        received. A 1-bit ACK/NACK is transmitted as a response for a        single downlink codeword, and a 2-bit ACK/NACK is transmitted as        a response for two downlink codewords.    -   CQI (Channel Quality Indicator): corresponds to feedback        information respective to a downlink channel. Feedback        information related to the MIMO (Multiple Input Multiple Output)        includes an RI (Rank Indicator), PMI (Precoding Matrix        Indicator), PTI (Precoding Type Indicator), and so on. 20 bits        are used for each subframe.

The amount (or size) of the control information (UCI) that can betransmitted by the user equipment from a subframe depends upon a numberof SC-FDMAs that are available for control information transmission. TheSC-FDMAs that are available for control information transmission refersto SC-FDMA symbols that remain after excluding the SC-FDMA symbol forreference signal transmission from the subframe. And, in case of asubframe having an SRS (Sounding Reference Signal) determined therein,the last SC-FDMA symbol of the subframe may also be excluded. Herein, areference signal is used for a coherent detection of the PUCCH. And, thePUCCH supports 7 different formats in accordance with the transmittedinformation.

Table 1 below shows a mapping relation between the PUCCH format and theUCI in the LTE system.

TABLE 1 PUCCH format Uplink Control Information (UCI) Format 1 SR(Scheduling Request) (non-modulated wave) Format 1a 1-bit HARQ ACK/NACK(SR present/absent) Format 1b 2-bit HARQ ACK/NACK (SR present/absent)Format 2 CQI (20 coded bits) Format 2 CQI and 1- or 2-bit HARQ ACK/NACK(20 bits) (corresponds only to extension CP) Format 2a CQI and 1-bitHARQ ACK/NACK (20 + 1 coded bits) Format 2b CQI and 2-bit HARQ ACK/NACK(20 + 2 coded bits)

FIG. 5 illustrates an exemplary procedure of physically mapping a PUCCHformat to a PUCCH domain.

Referring to FIG. 5, the PUCCH formats are mapped on the RBs startingfrom the band-edge and inwards by the order of PUCCH formats 2/2a/2b(CQI) (e.g., PUCCH region m=0, 1), PUCCH formats 2/2a/2b (CQI) or PUCCHformats 1/1a/1b (SR/HARQ ACK/NACK) (e.g., if present, PUCCH region m=2),and PUCCH formats 1/1a/1b (SR/HARQ ACK/NACK) (e.g., PUCCH region m=3, 4,5), thereby being transmitted. N_(RB) ⁽²⁾, the number of PUCCH RBs thatcan be used in the PUCCH format 2/2a/2b (CQI), is transmitted to theuser equipment within the cell through broadcast signaling.

FIG. 6 illustrates a slot level structure of PUCCH formats 2/2a/2b.PUCCH formats 2/2a/2b are used for CSI transmission. The CSI includesCQI, PMI, RI, and so on. In case of a normal CP (Cyclic Prefix), SC-FDMA#1 and #5 within the slot are used for DM RS (Demodulation ReferenceSignal) transmission. In case of an extended CP, only SC-FDMA #3 withinthe slot is used for the DM RS transmission.

Referring to FIG. 6, in a subframe level, 10-bit CSI information uses a(20,k) Reed-Muller code, which is punctured at a rate of ½, so as to bechannel-coded to 20 coded bits (not shown). Thereafter, the coded bitsmay be processed with scrambling (not shown), so as to be mapped to aQPSK (Quadrature Phase Shift Keying) constellation (QPSK modulation).The scrambling process may be performed by using a length-31 goldsequence, which is similar to PUSCH data. Accordingly, 10 QPSKmodulation symbols are generated, and 5 QPSK modulation symbols (d₀˜d₄)are transmitted from each slot through the corresponding SC-FDMA symbol.Each QPSK modulation symbol are used for modulating a length-12 base RSsequence (r_(u, 0)) prior to the IFFT (Inverse Fast Fourier Transform).Eventually, the RS sequence is processed with a Cyclic Shift (CS) in thetime domain in accordance with the QPSK modulation symbol value(d_(x)*r_(u,O) ^((αx)), x=0˜4). The RS sequence, which is multiplied bythe QPSK modulation symbol is then cyclic shifted (α_(cs,x,) x=1, 5). Incase the number of cyclic shifts is equal to N, N number of userequipments may be multiplexed over the same CSI PUCCH RB. Although theDM RS sequence is similar to the CSI sequence in the frequency domain,the CSI sequence is not modulated by the CSI modulation symbol.

A parameter or resource for periodic reporting of the CSI issemi-statically configured by higher layer (e.g., RRC (Radio ResourceControl)) signaling. For example, when PUCCH resource index n_(PUCCH)⁽²⁾ is set up for CSI transmission, the CSI is periodically transmittedover a CSI PUCCH, which is linked to the PUCCH resource index n_(PUCCH)⁽²⁾. The PUCCH resource index n_(PUCCH) ⁽²⁾ indicates a PUCCH RB and acyclic shift (α_(cs)).

FIG. 7 illustrates a slot level structure of PUCCH formats 1a/1b. PUCCHformats 1a/1b are used for ACK/NACK transmission. In case of a normalCP, SC-FDMA #2/#3/#4 within the slot are used for DM RS (DemodulationReference Signal) transmission. In case of an extended CP, SC-FDMA #2/#3within the slot are used for the DM RS transmission. Therefore, 4SC-FDMA symbols are being used for ACK/NACK transmission.

Referring to FIG. 7, 1-bit and 2-bit ACK/NACK information arerespectively modulated by using a BPSK modulation scheme and a QPSKmodulation scheme, thereby generating a single ACK/NACK modulationsymbol (d₀). In case of a positive ACK, the ACK/NACK information isgiven as 1, and, in case of a negative ACK, the ACK/NACK information isgiven as 0. Table 2 shown below represents a modulation table, which isdefined for PUCCH formats 1a and 1b in the conventional LTE system.

TABLE 2 PUCCH Format b(0), . . . , b(M_(bit) − 1) d(0) 1a 0 1 1 −1 1b 001 01 −j 10 j 11 −1

In addition to performing cyclic shift (α_(cs,x)) in the frequencydomain, just as the above-described CSI, the PUCCH formats 1a/1b mayalso use an orthogonal dispersion (or spreading) code (e.g.,Walsh-Hadamard or DFT code) (w₀,w₁,w₂,w₃), so as to perform time domaindispersion (or spreading). In case of the PUCCH formats 1a/1b, sincecode multiplexing is used in both frequency domain and time domain, alarger number of user equipments may be multiplexed over the same PUCCHRB.

The RSs that are each transmitted from different user equipments aremultiplexed by using the same method as the UCI. A number of cyclicshifts that are supported in an SC-FDMA symbol for the PUCCH ACK/NACK RBmay be cell-specifically configured by a higher layer signalingparameter Δ_(shift) ^(PUCCH). Δ_(shift) ^(PUCCH)ε{1, 2, 3} indicatesthat the shift values are respectively equal to 12, 6, and 4. A numberof dispersion codes that can actually be used for the ACK/NACK in thetime-domain CDM may be limited by the number of RS symbols. Due to asmall number of RS symbols, the multiplexing capacity of the RS symbolis smaller than the multiplexing capacity of the UCI symbol.

FIG. 8 illustrates an example of deciding a PUCCH resource for ACK/NACK.In the LTE system, the PUCCH resource for ACK/NACK is not allocated toeach user equipment in advance. Instead, multiple user equipments withina cell respectively use divided sections of multiple PUCCH resources ateach time point. More specifically, the PUCCH resource that is used bythe user equipment for transmitting the ACK/NACK corresponds to thePDCCH, which carries the scheduling information respective to thecorresponding downlink data. In each downlink subframe, a whole regionhaving the PDCCH transmitted thereto is configured of multiple CCEs(Control Channel Elements), and the PDCCH being transmitted to the userequipment is configured of one or more CCEs. Among the CCEs configuringthe PDCCH, which is received by the user equipment, the correspondinguser equipment transmits the ACK/NACK through a PUCCH resourcecorresponding to a specific CCE (e.g., the first CCE).

Referring to FIG. 8, in a Downlink Component Carrier (DL CC), eachrectangle (or square) represents a CCE. And, in an Uplink ComponentCarrier (UL CC), each rectangle (or square) represents a PUCCH resource.Each PUCCH index corresponds to a PUCCH resource for the ACK/NACK. Asshown in FIG. 8, when it is assumed that information on the PDSCH isbeing delivered through a PDCCH, which is configured of CCEs numbers4-6, the user equipment transmits the ACK/NACK through PUCCH number 4respective to CCE number 4, which corresponds to the first CCEconfiguring the PDCCH. FIG. 8 shows an example of a case when a maximumM number of PUCCHs exists in the UL CC, when a maximum N number of CCEsexists in the DL CC. Although N=M, the system may be designed so thatthe value of M and the value of N can be different from one another, andso that the mapping of the CCEs and PUCCHs can be overlapped.

More specifically, in the LTE system, the PUCCH resource index may bedecided as shown below.n ⁽¹⁾ _(PUCCH) =n _(CCE) +N ⁽¹⁾ _(PUCCH)  [Equation 1]

Herein, n⁽¹⁾ _(PUCCH) represents a resource index of PUCCH Format 1 fortransmitting ACK/NACK/DTX, N⁽¹⁾ _(PUCCH) indicates a signaling valuereceived from a higher layer, and n_(CCE) represents a lowest valueamong the CCE indexes that are used for the PDCCH transmission. A cyclicshift, an orthogonal dispersion code, and a PRB (Physical ResourceBlock) for PUCCH formats 1a/1b may be obtained from the n⁽¹⁾ _(PUCCH).

In case the LTE system operates in the TDD mode, the user equipmenttransmits a single multiplexed ACK/NACK signal respective to themultiple PDSCHs, which are received through the subframe at differenttime points. More specifically, the user equipment uses an ACK/NACKchannel selection method (simply referred to as a channel selectionmethod), so as to transmit the single multiplexed ACK/NACK signalrespective to the multiple PDSCHs. The ACK/NACK channel selection methodmay also be referred to as a PUCCH selection method. In the ACK/NACKchannel selection method, in case the user equipment has receivedmultiple sets of downlink data, the user equipment occupies multipleuplink physical channels in order to transmit the multiplexed ACK/NACKsignal. For example, in case the user equipment has received multiplePDSCHs, the user equipment may use a specific CCE of the PDCCH, whichindicates each PDSCH, so as to be capable of occupying the same numberof PUCCHs. In this case, based upon a combination of the information onwhich PUCCH is to be selected, among the plurality of occupied PUCCHS,and the modulated/encoded contents that are applied to the selectedPUCCH, the multiplexed ACK/NACK signal may be transmitted.

Table 3 shown below indicates the ACK/NACK channel selection method,which is defined in the LTE system.

TABLE 3 HARQ-ACK(0), HARQ-ACK(1), Subframe HARQ-ACK(2), HARQ-ACK(3) n⁽¹⁾_(PUCCH,X) b(0), b(1) ACK, ACK, ACK, ACK n⁽¹⁾ _(PUCCH,1) 1, 1 ACK, ACK,ACK, NACK/DTX n⁽¹⁾ _(PUCCH,1) 1, 0 NACK/DTX, NACK/DTX, NACK, DTX n⁽¹⁾_(PUCCH,2) 1, 1 ACK, ACK, NACK/DTX, ACK n⁽¹⁾ _(PUCCH,1) 1, 0 NACK, DTX,DTX, DTX n⁽¹⁾ _(PUCCH,0) 1, 0 ACK, ACK, NACK/DTX, NACK/DTX n⁽¹⁾_(PUCCH,1) 1, 0 ACK, NACK/DTX, ACK, ACK n⁽¹⁾ _(PUCCH,3) 0, 1 NACK/DTX,NACK/DTX, NACK/DTX, n⁽¹⁾ _(PUCCH,3) 1, 1 NACK ACK, NACK/DTX, ACK,NACK/DTX n⁽¹⁾ _(PUCCH,2) 0, 1 ACK, NACK/DTX, NACK/DTX, ACK n⁽¹⁾_(PUCCH,0) 0, 1 ACK, NACK/DTX, NACK/DTX, NACK/DTX n⁽¹⁾ _(PUCCH,0) 1, 1NACK/DTX, ACK, ACK, ACK n⁽¹⁾ _(PUCCH,3) 0, 1 NACK/DTX, NACK, DTX, DTXn⁽¹⁾ _(PUCCH,1) 0, 0 NACK/DTX, ACK, ACK, NACK/DTX n⁽¹⁾ _(PUCCH,2) 1, 0NACK/DTX, ACK, NACK/DTX, ACK n⁽¹⁾ _(PUCCH,3) 1, 0 NACK/DTX, ACK,NACK/DTX, NACK/DTX n⁽¹⁾ _(PUCCH,1) 0, 1 NACK/DTX, NACK/DTX, ACK, ACKn⁽¹⁾ _(PUCCH,3) 0, 1 NACK/DTX, NACK/DTX, ACK, NACK/DTX n⁽¹⁾ _(PUCCH,2)0, 0 NACK/DTX, NACK/DTX, NACK/DTX, ACK n⁽¹⁾ _(PUCCH,3) 0, 0 DTX, DTX,DTX, DTX N/A N/A

In Table 3, HARQ-ACK(i) represents an HARQ ACK/NACK/DTX result of ani-^(th) data unit (0≦i≦3). The DTX (Discontinuous Transmission)indicates a case when no data unit transmission corresponding to theHARQ-ACK(i) exists, or a case when the user equipment is incapable ofdetecting the presence (or existence) of a data unit corresponding tothe HARQ-ACK(i). With respect to each data unit, a maximum of 4 PUCCHresources (i.e., n⁽¹⁾ _(PUCCH,0)˜n⁽¹⁾ _(PUCCH,3)) may be occupied. Themultiplexed ACK/NACK may be transmitted through a single PUCCH, which isselected from the occupied PUCCH resources. Herein, n⁽¹⁾ _(PUCCH,X),which is indicated in Table 3 represents a PUCCH resource that is usedfor actually transmitting the ACK/NACK. And, b(0)b(1) represents twobits that are being transmitted through the selected PUCCH resource andis modulated by using the QPSK method (or scheme). For example, when theuser equipment has successfully decoded 4 data units, the user equipmenttransmits (1,1) to the base station through the PUCCH resource, which isconnected to n⁽¹⁾ _(PUCCH,1). Since it is difficult to indicate allACK/NACK assumptions, in which the PUCCH resource and the QPSK symbolcan be combined, with the exception for a few cases, the NACK is coupledwith the DTX (NACK/DTX, N/D).

FIG. 9 illustrates an exemplary method of multiplexing an ACK/NACK withan SR.

The structure of the SR PUCCH format 1 is identical to the ACK/NACKPUCCH format 1a/1b shown in FIG. 9. The SR uses On-Off keying. Morespecifically, in order to request a PUSCH resource (positive SR), theuser equipment transmits an SR having a modulation symbol d(0)=1. And,when scheduling is not requested (negative SR), the user equipment doesnot perform any transmission (or does not transmit anything). Since thesame PUCCH structure for the ACK/NACK is re-used for the SR, differentPUCCH resource indexes existing in the same PUCCH region (e.g., acombination of different cyclic time shift/orthogonal code) may beallocated to the SR (format 1) or the HARQ ACK/NACK (formats 1a/1b). ThePUCCH resource index m_(PUCCH,SR1) ⁽¹⁾, which is to be used by the userequipment for SR transmission may be determined by UE-specific higherlayer signaling.

When the user equipment is required to transmit a positive SR in asubframe being scheduled to perform CQI transmission, the CQI isdropped, and only the SR is transmitted. Similarly, when a simultaneousSR and SRS (Sounding RS) transmission situation occurs, the userequipment drops the CQI and transmits only the SR. In case the SR andthe ACK/NACK are generated from the same subframe, the user equipmentmay transmit the ACK/NACK over the SR PUCCH resource, which is allocatedfor the positive SR. In case of the negative SR, the user equipmenttransmits the ACK/NACK over the allocated HARD-ACK PUCCH resource. FIG.9 shows an exemplary mapping constellation for a simultaneoustransmission of the ACK/NACK and the SR. More specifically, FIG. 9 showsan example of a case when the NACK (or NACK, NACK, in case of two MIMOcodewords) is modulated and mapped to +1 (n RS modulation). Accordingly,when a DTX (Discontinuous Transmission) occurs, the signal is processedas a NACK.

FIG. 10 illustrates an exemplary Carrier Aggregation (CA) communicationsystem. An LTE-A system uses a carrier aggregation or bandwidthaggregation technique, which uses a larger uplink/downlink bandwidth bygrouping (or gathering) multiple uplink/downlink frequency blocks inorder to use a broader frequency bandwidth. Each frequency block istransmitted by using a Component Carrier (CC). Herein, a componentcarrier may be understood as a carrier frequency (or central carrier,central frequency for the respective frequency block.

Referring to FIG. 10, multiple uplink/downlink Component Carriers (CCs)may be grouped (or gathered), so as to support a broader (or wider)uplink/downlink bandwidth. Each CC may be adjacent to one another ornon-adjacent to one another in the frequency domain. The bandwidth ofeach component carrier may be independently decided. Asymmetric carrieraggregation, wherein the number of UL CCs is different from the numberof DL CCs, may also be used. For example, when the number of DL CCs isequal to 2, and when the number of UL CCs is equal to 1, configurationshaving a 2:1 correspondence may be formed. Additionally, even if theoverall system band is configured of N number of CCs, the frequency bandthat may be monitored/received by a specific user equipment may belimited to M(<N) number of CCs. Various parameters respective to carrieraggregation may be determined by using cell-specific, UE group-specific,or UE-specific methods. Meanwhile, control information may be determinedto be transmitted and/or received (or transceived) only through aspecific CC. Such specific CC may be referred to as a Primary CC (PCC)(or anchor CC), and the remaining CCs may be referred to as SecondaryCCs (SCCs).

The LTE-A system uses the concept of a cell in order to manage radioresources. A cell is defined as a combination of a downlink resource andan uplink resource, and the uplink resource does not correspond to anessential element. Therefore, the cell may be configured only of adownlink resource, or the cell may be configured of both the downlinkresource and the uplink resource. In case carrier aggregation issupported, a linkage between the carrier frequency of a downlinkresource (or DL CC) and the carrier frequency of an uplink resource (orUL CC) may be indicated by the system information. A cell that isoperated over the primary frequency (or PCC) may be referred to as aPrimary Cell (PCell), and a cell that is operated over the secondaryfrequency (or SCC) may be referred to as a Secondary Cell (SCell). ThePCell is used, when the user equipment performs an initial connectionestablishment process or a connection re-establishment process. ThePCell may also indicate a cell that is indicated during a handoverprocedure. The SCell may be configured after the RRC connection isestablished, and the SCell may be used for providing additional radioresource. The PCell and the SCell may be collectively referred to as aserving cell. Accordingly, in case of a user equipment that is in anRRC_CONNECTED state, yet not set up with carrier aggregation, or doesnot support carrier aggregation, only a single serving cell configuredonly of the PCell may exist. Conversely, in case of a user equipmentthat is in an RRC_CONNECTED state and set up with carrier aggregation,one or more serving cells may exist, and a PCell and all of the SCellsmay be included in all of the serving cells. In order to perform carrieraggregation, after an initial security activation process is initiated,the network may configure one or more SCells, so that the one or moreSCells can added to the PCell, which is initially configured, for a userequipment supporting carrier aggregation.

When cross-carrier scheduling (or cross-CC scheduling) is applied, thePDCCH for downlink allocation may be transmitted to DL CC #0, and thecorresponding PDSCH may be transmitted to DL CC #2. In order to performcross-CC scheduling, the adoption of a carrier indicator field (CIF) maybe considered. The presence or absence of the CIF within the PDCCH maybe configured through higher layer signaling (e.g., RRC signaling) byusing a half-static and UE-specific (or UE group-specific) method. Abase line of the PDCCH transmission may be summarized as shown below.

-   -   CIF disabled: the PDCCH within the DL CC allocates PDSCH        resource within the same DL CC or allocates a PUSCH resource        within a linked UL CC.    -   CIF enabled: the PDCCH within the DL CC is capable of allocating        a PDSCH or PUSCH within a specific DL/UL CC, among the plurality        of aggregated DL/UL CCs by using the CIF.

When the CIF exists, the base station may allocate a PDCCH monitoring DLCC set in order to reduce BD complexity of the user equipment. As aportion of the overall aggregated DL CC, the PDCCH monitoring DL CC setincludes one or more DL CCs, and the user equipment may performdetection/decoding of the PDCCH only within the corresponding DL CC.More specifically, when the base station schedules the PDSCH/PUSCH tothe user equipment, the PDCCH is transmitted only through the PDCCHmonitoring DL CC set. The PDCCH monitoring DL CC set may be determinedby using the UE-specific method, the UE-group-specific method, or thecell-specific method. The term “PDCCH monitoring DL CC” may be replacedwith other equivalent terms such as monitoring carrier, monitoring cell,and so on. Furthermore, the aggregated CC designated to the userequipment may also be replaced with other equivalent terms such as aserving CC, a serving carrier, a serving cell, and so on.

FIG. 11 illustrates an exemplary cross-carrier scheduling. Herein, itwill be assumed that 3 DL CCs are aggregated. And, it will also beassumed that DL CC A is determined as the PDCCH monitoring DL CC. DL CCA˜C may also be referred to as service CCs, service carriers, servingcells, and so on. When the CIF is disabled, each DL CC may transmit onlythe PDCCH scheduling its own PDSCH without the CIF, in accordance withthe LTE PDCCH rule. Conversely, when the CIF is enabled by UE-specific(or UE-group specific or cell-specific) higher layer signaling, DL CC A(monitoring DL CC) may use the CIF, so as to transmit the PDCCHscheduling the PDSCH of DL CC A and also to transmit the PDCCHscheduling the PDSCH of other CCs. In this case, the PDCCH is nottransmitted from DL CC B/C, which are not determined as the PDCCHmonitoring DL CC. In the LTE-A system, it may be considered that diverseACK/NACK information/signals respective to the multiple PDSCHs, whichare transmitted through multiple DL CCs, may be transmitted through aspecific UL CC. In order to do so, it may be considered that, unlike theACK/NACK transmission using the PUCCH formats 1a/1b of the conventionalLTE system, the diverse ACK/NACK information are first processed withjoint coding (e.g., Reed-Muller code, Tail-biting convolutional code,and so on), and that diverse ACK/NACK information/signals aretransmitted by using PUCCH format 2 or by using a new PUCCH format(referred to as an E-PUCCH (Enhanced PUCCH) format or PUCCH format X).The E-PUCCH format includes a Block-spreading based PUCCH format, asshown below. After performing joint coding, as an example, an ACK/NACKtransmission using the PUCCH format 2/E-PUCCH format, the PUCCH format2/E-PUCCH format may be used for UCI transmission without anylimitations. For example, the PUCCH format 2/E-PUCCH format may be usedfor transmitting an ACK/NACK, CSI (e.g., CQI, PMI, RI, PTI, and so on),SR, or for collectively transmitting 2 or more types of information. Inthe description of the present invention, the PUCCH format 2/E-PUCCHformat may be used for transmitting a joint-coded UCI codewordregardless of the type/number/size of the UCI.

FIG. 12 illustrates an exemplary E-PUCCH format based on block-spreading(or block-dispersion) in a slot level. In the PUCCH format 2 of theconventional LTE system, one symbol sequence (FIG. 6, d0˜d4) istransmitted over the time domain, and user equipment multiplexing isperformed by using a CS (α_(cs,x), x=0˜4) of a CAZAC (Constant-AmplitudeZero Auto-Correlation) sequence (r_(u,O)), as shown in FIG. 6.Conversely, in case of the block-spreading based E-PUCCH format, onesymbol sequence is transmitted over the frequency domain, and userequipment multiplexing is performed by using an OCC (Orthogonal CoverCode) based time-domain dispersion (or spreading). More specifically,the symbol sequence is time-domain dispersed (or spread) by the OCC,thereby being transmitted. By using the OCC, the same RB may multiplexthe control signals of multiple user equipments.

Referring to FIG. 12, by using a length-5 (SF (Spreading Factor)=5) OCC(C1˜C5), 5 SC-FDMA symbols (i.e., UCI data part) are generated from onesymbol sequence ({d1, d2, . . . }). Herein, the symbol sequence ({d1,d2, . . . }) may signify a modulation symbol sequence or a codeword bitsequence. In case the symbol sequence ({d1, d2, . . . }) represents thecodeword bit sequence, the block diagram of FIG. 13 further includesmodulation block. Although it is shown in the drawing that a total of 2RS symbols (i.e., RS part) are used during 1 slot, diverse appliedvariations, such as a method of using an RS part, which is configured of3 RS symbols, and using a UCI data part, which is configured by using anOCC of SF=4, may be considered. Herein, the RS symbols may be generatedfrom a CAZAC sequence having a specific cyclic shift. Additionally, theRS may be transmitted in a format having multiple RS symbols of the timedomain be applied with (be multiplied by) a specific OCC. Theblock-spread UCI is transmitted to the network after being processedwith an FFT (Fast Fourier Transform) procedure and an IFFT (Inverse FastFourier Transform) procedure in SC-FDMA symbol units. More specifically,unlike the PUCCH format 1 or 2 groups of the conventional LTE system,the block-spreading method modulates the control information (e.g.,ACK/NACK, and so on) by using the SC-FDMA method.

FIG. 13 illustrates an exemplary E-PUCCH format based on block-spreading(or block-dispersion) in a subframe level.

Referring to FIG. 13, in slot 0, a symbol sequence ({d′0˜d′11}) ismapped to a subcarrier of an SC-FDMA symbol, and the symbol sequence ismapped to 5 SC-FDMA symbols by a block-spreading method using an OCC(C1˜C5). Similarly, in slot 1, a symbol sequence ({d′12˜d′23}) is mappedto a subcarrier of an SC-FDMA symbol, and the symbol sequence is mappedto 5 SC-FDMA symbols by a block-spreading method using an OCC (C1˜C5).Herein, the symbol sequence ({d′0˜d′11} or {d′12˜d′23}), which is shownin each slot, represents a sequence format having FFT or FFT/IFFTapplied to the symbol sequence ({d1, d2, . . . }) of FIG. 13. In casethe symbol sequence ({d′0˜d′11} or {d′12˜d′23}) corresponds to a formathaving FFT applied to the symbol sequence ({d1, d2, . . . }) of FIG. 13,IFFT may be additionally applied to {d′0˜d′11} or {d′12˜d′23} forSC-FDMA generation. The overall symbol sequence ({d′0˜d′23}) isgenerated by performing joint-coding on one or more UCIs, and the firsthalf ({d′0˜d′11}) is transmitted through slot 0, and the second half({d′0˜d′11}) is transmitted through slot 1. Although it is not shown inthe drawing, the OCC may be modified to slot units, and the UCI data maybe scrambled in SC-FDMA symbol units.

Hereinafter, for simplicity in the description of the present invention,a UCI (e.g., multiple ACK/NACKs) transmission method based on channelcoding using the PUCCH format 2 or E-PUCCH format will be referred to asa “multi-bit UCI coding” transmission method. For example, in case ofthe ACK/NACK, the multi-bit UCI coding transmission method correspondsto a method that performs joint coding on ACK/NACK or DTX information(signifying that the PDCCH cannot be received/detected) respective tothe PDCCH, which indicates PDSCH and/or SPS (Semi-Persistent Scheduling)release of multiple DL cells, and that transmits the generated and codedACK/NACK block. For example, it will be assumed that the user equipmentis operated in the SU-MIMO mode in a particular DL cell and receives 2codewords. In this case, a total of 4 feedback states, such as ACK/ACK,ACK/NACK, NACK/ACK, and NACK/NACK, may exist, or a maximum of 5 feedbackstates including DTX may exist. If the user equipment receives a singlecodeword, a maximum of 3 feedback states, such as ACK, NACK, and DTX,may exist (if the NACK is processed identically as the DTX, a total of 2feedback states ACK and NACK/DTX may exist). Accordingly, if the userequipment integrates a maximum of 5 DL cells, and if the user equipmentis operated in the SU-MIMO (Single User Multiple Input Multiple Output)mode in each cell, a maximum of 5⁵ transmittable feedback states mayexist. Therefore, the required ACK/NACK payload size is equal to atleast 12 bits. If the DTX is processed identically as the NACK, thenumber of feedback states becomes equal to 4⁵, and the required ACK/NACKpayload size is equal to at least 10 bits.

Meanwhile, an implicit ACK/NACK channel selection method, which uses aPUCCH resource corresponding to the PDCCH scheduling each PDSCH of therespective user equipment in order to ensure PUCCH resource (i.e., (aPUCCH resource) being linked with the smallest (or lowest) CCE index) isessentially used in the ACK/NACK multiplexing method (i.e., ACK/NACKchannel selection method) (see Table 3), which is applied in theconventional LTE TDD system. However, when applying the implicit methodby using the PUCCH resource within different RBs, degradation in thesystem performance may occur. Therefore, the LTE-A system mayadditionally consider an “explicit ACK/NACK channel selection” method,which uses a PUCCH resource being reserved in advance for each userequipment (preferably multiple PUCCH resource existing in the same RB orneighboring (or adjacent) RBs) through RRC signaling, and so on.Furthermore, the LTE-A system also considers ACK/NACK transmissionthrough one UE-specific UL cell (e.g., PCell).

Table 4 below shows an example of explicitly indicating a PUCCH resourcefor HARD ACK.

TABLE 4 HARQ-ACK resource value for PUCCH (ARI) n_(PUCCH) 00 1^(st)PUCCH resource value configured by a higher layer 01 2^(nd) PUCCHresource value configured by a higher layer 10 3^(rd) PUCCH resourcevalue configured by a higher layer 11 4^(th) PUCCH resource valueconfigured by a higher layer

ARI: ACK/NACK Resource Indicator. In Table 4, the higher layer includesan RRC layer, and the ARI value may be indicated through the PDCCH,which carries a DL grant. For example, the ARI value may be indicated byusing an SCell PDCCH and/or a TPC (Transmit Power Control) field of oneor more PCell PDCCHs that do not correspond to the DAI initial value.

FIG. 14 illustrates exemplary operations of a base station and a userequipment in a DL CC modification section. In the LTE-A system, a DL CCset that is aggregated by the user equipment may be UE-specificallyallocated and reconfigured through RRC signaling.

Referring to FIG. 14, when the base station changes (or modifies) the DLCC(s) that can be used by the user equipment by performing RRCreconfiguration or L1/L2 control signaling, the timing between the basestation and the user equipment, at which the changed (or modified) DLCC(s) can be applied, may be different from one another. For example,when the base station changes the number of CCs that can be used by theuser equipment from 3 to 2, the time point at which the base stationchanges the number of DL CCs from 3 to 2 and transmits the downlinkdata, and the time point at which the user equipment changes the numberof serving DL CCs from 3 to 2 may be different from one another.Additionally, even though the base station directs (or indicates) achange in the number of CCs, if the user equipment fails to receive theabove-mentioned direction (or indication), a time interval may occur,wherein the number of DL CCs known by the user equipment is differentfrom the number of DL CCs known by the base station.

Accordingly, the base station may expect to receive ACK/NACK respectiveto 2 DL CCs, while the user equipment transmits ACK/NACK respective to 3DL CCs. Alternatively, the base station may expect to receive ACK/NACKrespective to 3 DL CCs, while the user equipment transmits ACK/NACKrespective to 2 DL CCs. In this case, a problem may occur in that theACK/NACK cannot be accurately demodulated. For example, in case of themulti-bit UCI coding method, the size/configuration of the ACK/NACKpayload known and recognized by the base station and the user equipmentmay be different from one another. Furthermore, in case of the ACK/NACKchannel selection method, the mapping/configuration of the ACK/NACKstate recognized by the base station and the user equipment may bedifferent from one another.

In order to resolve the above-described problems, when one or more CCs,including at least the DL PCC (also referred to as a DL PCell), arescheduled, when the states of the remaining CCs (i.e., DL SCCs (alsoreferred to as DL SCells)), excluding the DL PCC, all correspond to NACKor DTX, it may be considered to transmit the ACK/NACK by using animplicit PUCCH resource (e.g., see Equation 1), which is linked to thePDCCH scheduling the DL PCC. In other words, when the ACK/NACK state forthe DL PCC (or each CW of the DL PCC) corresponds to “A” or “N”, andwhen the ACK/NACK state for each of the DL SCCs (or each CW of the DLSCCs) corresponds to “N/D”, limitations may be made so that an implicitPUCCH resource being linked to the PDCCH for the DL PCC, in accordancewith the method defined in the conventional LTE system, can be usedinstead of the explicit PUCCH resource (also referred to as “PCCfallback” or “PCell fallback” for simplicity). Most particularly, whenperforming PCC fallback, a PUCCH format that is for the transmission ofthe ACK/NACK state and a modulation symbol that is transmitted throughthe PUCCH format may be limited to follow the method defined in theconventional LTE system. For example, when performing PCC fallback, theACK/NACK state may be transmitted by using the PUCCH format 1a/1b shownin FIG. 7 and the modulation table (see Table 2).

More specifically, a case when the transmission mode of the PCC is setto a non-MIMO mode (single CW) will first be described. Herein, 2ACK/NACK states will be assumed, wherein the ACK/NACK state for the PCCis “A” or “N”, and wherein the ACK/NACK state for all SCCs (or each CWof the SCCs) is “N/D”. In this case, the ACK/NACK states may be mappedto 2 constellation points on the implicit PUCCH resource, which islinked to the PDCCH scheduling the PCC. Herein, the 2 constellationpoints for the ACK/NACK states may preferably be limited to 2constellation points, which are defined for the transmission of PUCCHformat 1a ACK/NACK respective to a single CW transmission in a singleCC. Alternatively, the 2 constellation points for the ACK/NACK statesmay be limited to 2 constellation points for “AA” and “NN”, among the 4constellation points, which are defined for the transmission of PUCCHformat 1b ACK/NACK in a single CC. More specifically, the mappingpositions of the ACK/NACK states on the constellation may be decidedwith reference to “A”, “N” of the PCC. Preferably, the mapping positionsof the ACK/NACK states on the constellation may be limited so that “A”,“N” of the PCC are placed at the same positions as the “A”, “N” of PUCCHformat 1a, or at the same positions as the “AA”, “NN” of PUCCH format1b.

Hereinafter, a case when the PCC is configured as the MIMO mode (e.g.,two CWs or 2 TBs) will be described. Herein, 4 ACK/NACK states will beassumed, wherein the ACK/NACK state for the PCC is “A+A” or “A+N” or“N+A” or “N+N”, and wherein the ACK/NACK state for all SCCs (or each CWof the SCCs) is “N/D”. In this case, the ACK/NACK states may be mappedto 4 constellation points on the implicit PUCCH resource, which islinked to the PDCCH scheduling the PCC. Herein, the 4 constellationpoints for the ACK/NACK states may preferably be limited to 4constellation points, which are defined for the transmission of PUCCHformat 1b ACK/NACK respective to the transmission of two CWs in a singleCC. The positions at which the ACK/NACK states are mapped on theconstellation may be decided with reference to “A”, “N” of the each CWof the PCC. In the description of the present invention, “N” of the PCCincludes NACK, DTX, or NACK/DTX. Preferably, on the constellation, the“A”, “N” of each CW included in the PCC are mapped to the same positionsas the “A”, “N” of each CW for of PUCCH format 1b.

FIG. 15 illustrates an exemplary PUCCH formats 1a/1b based ACK/NACKchannel selection method respective to the transmission of a single/twoCW(s) in a single CC according to the conventional LTE. FIG. 16illustrates an exemplary ACK/NACK transmitting method according to a PCCfallback method, when the PCC is configured as a non-MIMO or MIMOtransmission mode, in a case when 3 CCs (PCC, CC1, CC2) are aggregated.In this example, it will be assumed that the SCCs (i.e., CC1, CC2) areall configured as the non-MIMO transmission mode for simplicity.

Referring to FIG. 15˜16, when the ACK/NACK state is “A” or “N” for thenon-MIMO mode PCC, and when the ACK/NACK state for all of the SCCs is“N/D”, an “explicit ACK/NACK channel selection” method is not applied(i.e., PCC fallback). More specifically, the ACK/NACK state (PCC, CC1,CC2)=(A, N/D, N/D), (N, N/D, N/D) is mapped/transmitted to/using animplicit PUCCH resource that is linked to the PDCCH scheduling the PCC.In this case, the mapping relation between the ACK/NACK state and theconstellation mapping follows the rule of the conventional LTE systemshown in FIG. 15 with reference to the ACK/NACK for the PCC.

Additionally, when the ACK/NACK state is “A+A” or “A+N” or “N+A” or“N+N” for the MIMO mode PCC, and when the ACK/NACK state for all of theSCCs is “N/D”, an “explicit ACK/NACK channel selection” method is notapplied (i.e., PCC fallback). In this case, the mapping relation betweenthe ACK/NACK state and the constellation mapping follows the rule of theconventional LTE system shown in FIG. 15 with reference to the ACK/NACKfor the PCC. More specifically, the ACK/NACK state (PCC CW1, PCC CW2,CC1, CC2)=(A, A, N/D, N/D), (A, N, N/D, N/D), (N, A, N/D, N/D), (N, N,N/D, N/D) is mapped/transmitted to/using an implicit PUCCH resource thatis linked to the PDCCH scheduling the PCC.

Even if the PCC is configures as the MIMO mode, one CW or multiple CWsbeing transmitted on the PCC may be scheduled through a single PCCPDCCH. Accordingly, in order to perform transmission of the ACK/NACKrelated to the PCC, a single implicit PUCCH resource is occupied.

Tables 5˜6 respectively show exemplary ACK/NACK state mapping tables inaccordance with FIG. 16. Tables 5˜6 respectively show a partial state,among the total ACK/NACK states, when PCC fallback is being performed.The mapping relation between the PUCCH resource, which is used fortransmitting the remaining ACK/NACK state, and the bit value may bearbitrarily defined in the present invention. More specifically, themapping relation between the PUCCH resource, which is used fortransmitting the remaining ACK/NACK state, and the bit value is don'tcare (irrelevant) in the present invention.

TABLE 5 PCC SCC1 HARQ- HARQ- SCC2 ACK(0) ACK(1) HARQ-ACK(2) b(0), . . ., b(M_(bit) − 1) d(0) ACK NACK/DTX NACK/DTX 1 (11) −1 NACK NACK/DTXNACK/DTX 0 (00) +1

Herein, HARQ-ACK(0) represents an ACK/NACK/DTX response for a CW (or TB)of the PCC. HARQ-ACK(1) represents an ACK/NACK/DTX response for SCC1.HARQ-ACK(2) represents an ACK/NACK/DTX response for CW1 of SCC2. TheACK/NACK/DTX response includes ACK, NACK, DTX or NACK/DTX. In the PCC,the NACK includes NACK, DTX or NACK/DTX. d(0) corresponding to theACK/NACK state is transmitted by using an implicit PUCCH resource, andthe implicit PUCCH resource is liked to a PDCCH that is used forscheduling the CW (or TB) of the PCC (e.g., see Equation 1). PUCCHformats 1a/1b and, more preferably, PUCCH format 1b may be used.

TABLE 6 PCC SCC1 HARQ- HARQ- HARQ- SCC2 b(0), . . . , ACK(0) ACK(1)ACK(2) HARQ-ACK(3) b(M_(bit) − 1) d(0) ACK ACK NACK/DTX NACK/DTX 11 −1ACK NACK NACK/DTX NACK/DTX 10 j NACK ACK NACK/DTX NACK/DTX 01 −j NACKNACK NACK/DTX NACK/DTX 00   1

Herein, HARQ-ACK(0) represents an ACK/NACK/DTX response for CW1 (or TB1)of the PCC, and HARQ-ACK(1) represents an ACK/NACK/DTX response for CW2(or TB2) of the PCC. HARQ-ACK(2) represents an ACK/NACK/DTX response forSCC1. HARQ-ACK(3) represents an ACK/NACK/DTX response for CW1 of SCC2.The ACK/NACK/DTX response includes ACK, NACK, DTX or NACK/DTX. In thePCC, the NACK includes NACK, DTX or NACK/DTX. d(0) corresponding to theACK/NACK state is transmitted by using an implicit PUCCH resource, andthe implicit PUCCH resource is liked to a PDCCH that is used forscheduling the CW (or TB) of the PCC (e.g., see Equation 1). PUCCHformat 1b may be used.

In FIG. 16, it is assumed that the number of SCCs is equal to 2, andthat each SCC is set to a non-MIMO mode. However, the above-describedassumption is merely exemplary. And, therefore, the number of SCCs andthe transmission mode of each SCC may be diversely varied.

Meanwhile, when applying the multi-bit UCI coding and (explicit)ACK/NACK channel selection method, various methods may be considered forthe SR transmission. Hereinafter, when multiple CCs (in other words,carriers, frequency resources, cells, and so on) are aggregated, amethod for efficiently transmitting the uplink control information and,more preferably, the ACK/NACK and the SR, and a resource allocationmethod for the same will be described in detail.

For simplicity in the description, it will be assumed in the followingdescription that 2 CCs are configured for one user equipment. Also, incase the CC is configured a non-MIMO mode, it will be assumed that amaximum of one transport block (or codeword) can be transmitted at asubframe k of the corresponding CC. Additionally, in case the CC isconfigured as a MIMO mode, it will also be assumed that a maximum of mnumber (e.g., 2) of transport blocks (or codewords) can be transmittedat a subframe k of the corresponding CC. Information on whether or notthe CC is configured as the MIMO mode may be known by using thetransmission mode, which is configured by a higher layer. Furthermore,it will also be assumed that the number of ACK/NACKs for thecorresponding CC is configured as 1 ACK/NACK (non-MIMO) or m ACK/NACKs(MIMO) in accordance with the configured transmission mode of thecorresponding CC, regardless of the number of actually transmittedtransport blocks (or codewords).

First of all, the terms that are used in the description of the presentinvention will hereinafter be described.

HARQ-ACK: indicates a reception response result for a downlinktransmission (e.g., PDSCH or SPS release PDCCH), i.e., an ACK/NACK/DTXresponse (simply referred to as an ACK/NACK response). ACK/NACK/DTXresponse represents ACK, NACK, DTX or NACK/DTX. Also, the terms“HARQ-ACK for (or respective to) a specific CC” or “HARQ-ACK of aspecific CC” indicates an ACK/NACK response respective to a downlinksignal (e.g., PDSCH) associated with the respective CC (e.g., scheduledto the respective CC). Furthermore, the ACK/NACK state represents acombination corresponding to multiple HARQ-ACKs. Herein, the PDSCH maybe replaced with a transport block or a codeword.

PUCCH index: corresponds to a PUCCH resource. The PUCCH index indicates,for example, a PUCCH resource index. The PUCCH resource index is mappedto at least one of an orthogonal cover (OC), a cyclic shift (CS), and aPRB. In case the ACK/NACK channel selection method is applied, the PUCCHindex includes a PUCCH (resource) index for the PUCCH format 1b.

PUCCH resource linked to a CC: represents a PUCCH resource (see Equation1, implicit PUCCH resource) linked to the PDCCH corresponding to thePDSCH on the respective CC, or represents a PUCCH resource (explicitPUCCH resource) indicated/allocated by a PDCCH, which corresponds to aPDSCH on the respective CC. In the explicit PUCCH resource method, thePUCCH resource may be indicated/allocated by using an ARI (ACK/NACKResource Indicator) of the PDCCH.

ARI (ACK/NACK Resource Indicator): is used for the purpose of indicatingthe PUCCH resource. For example, the ARI may be used for the purpose ofnotifying a resource modification value (e.g., offset) respective to aspecific PUCCH resource (group) (which is configured by a higher layer).In another example, the ARI may be used for the purpose of notifying aspecific PUCCH resource (group) index within a specific PUCCH resource(group) set (which is configured by a higher layer). The ARI may beincluded in a TPC (Transmit Power Control) field of the PDCCHcorresponding to the PDSCH on the SCC. The PUCCH power control may beperformed through the TPC field within the PDCCH scheduling the PCC(i.e., the PDCCH corresponding to the PDSCH on the PCC). Furthermore,the ARI may be included in the TPC field of the remaining PDCCHs, afterexcluding the PDCCH that have a DAI (Downlink Assignment Index) initialvalue and schedules a specific cell (e.g., PCell). The ARI may be usedinterchangeably with an HARQ-ACK resource indication value.

Implicit PUCCH resource: indicates a PUCCH resource/index that is linkedto a lowest CCE index of the PDCCH, which schedules the PCC (seeEquation 1).

Explicit PUCCH resource: The explicit PUCCH resource may be indicated byusing the ARI. When the ARI cannot be applied, the explicit PUCCHresource may correspond to a PUCCH resource, which is fixed in advanceby higher layer signaling. The explicit PUCCH index(s) may be allocatedto one user equipment may so that all indexes are adjacent to oneanother, indexes for each resource group are adjacent to one another, orall indexes are independent from one another.

CC scheduling PDCCH: represents a PDCCH that schedules the PDSCH on acorresponding CC. More specifically, the CC scheduling PDCCH indicates aPDCCH corresponding to the PDSCH on the corresponding CC.

PCC PDCCH: indicates the PDCCH that schedules the PCC. Morespecifically, the PCC PDCCH indicates a PDCCH corresponding to the PDSCHon the PCC. When it is assumed that cross-carrier scheduling is notallowed for the PCC, the PCC PDCCH is transmitted only on the PCC.

SCC PDCCH: indicates the PDCCH that schedules the SCC. Morespecifically, the SCC PDCCH indicates a PDCCH corresponding to the PDSCHon the SCC. When it is assumed that cross-carrier scheduling is allowedfor the SCC, the SCC PDCCH may be transmitted on the PCC. On the otherhand, if the cross-carrier scheduling is not allowed for the SCC, theSCC PDCCH is transmitted only on the SCC.

SR subframe: represents an uplink subframe that is configured for an SRtransmission. Depending upon the exemplary implementation, the SRsubframe may be defined as a subframe on which the SR information istransmitted, or a subframe on which the transmission of the SRinformation is allowed. The SR subframe may be specified by higher layersignaling (e.g., cyclic period, offset).

SR PUCCH resource: indicates a PUCCH resource that is configured for anSR transmission. The SR PUCCH resource is configured by a higher layerand may be specified, for example, by the CS, OCC, PRB, and so on.

HARQ-ACK PUCCH resource: indicates a PUCCH resource that is configuredfor the HARQ-ACK transmission. The HARQ-ACK PUCCH resource is allocatedexplicitly or implicitly. The HARQ-ACK PUCCH resource may be specified,for example, by the CS, OCC, PRB, or OCC, PRB in accordance with thePUCCH format.

ACK/NACK bundling: indicates that a logical AND operation is performed(or processed) to multiple ACK/NACK responses. More specifically, whenall of the multiple ACK/NACK responses correspond to ACK, the ACK/NACKbundling result becomes ACK. And, if any one of the multiple ACK/NACKresponses corresponds to NACK (or NACK/DTX), the ACK/NACK bundlingresult becomes NACK (or NACK/DTX).

Spatial bundling: represents performing a bundling on ACK/NACK(s) for apart or all of the transport block(s) on a corresponding CC.

CC bundling: represents performing a bundling on ACK/NACK(s) for a partor all of the transport block(s) on multiple CCs.

Cross-CC scheduling: represents an operation wherein all PDCCHs arebeing scheduled/transmitted through a single PCC.

Non-cross-CC scheduling: represents an operation wherein a PDCCH thatschedules each CC is scheduled/transmitted through the corresponding CC.

The LTE-A system considers allowing cross-carrier scheduling for the DLPCC yet considers allowing only self-carrier scheduling for the DL SCC.In this case, a PDCCH scheduling a PDSCH of a DL PCC may be transmittedonly on the DL PCC. Conversely, a PDCCH scheduling a PDSCH of the DL SCCmay be transmitted on the DL PCC (cross-carrier scheduling), or on acorresponding DL SCC (self-carrier scheduling).

Embodiment 1

FIG. 17 illustrates an exemplary UCI transmitting method according to anembodiment of the present invention. It will be assumed in this examplethat the user equipment is configured to use the ACK/NACK channelselection method in the CA-based FDD system. It will also be assumedthat this example is configured with one PCC and one SCC. The drawingshows an exemplary PUCCH resource allocation (or assignment) procedure,and the drawing is simply illustrated by focusing on the ACK/NACK andthe SR. With respect to the ACK/NACK and the SR, three cases may beconsidered as shown below.

-   -   Case 1: transmit ACK/NACK at a non-SR subframe    -   Case 2-1: transmit ACK/NACK at an SR subframe, negative SR    -   Case 2-2: transmit ACK/NACK at an SR subframe, positive SR

Referring to FIG. 17, in case of Cases 1 and 2-1, the ACK/NACK state istransmitted by using the ACK/NACK channel selection method and theHARQ-ACK PUCCH resource. For example, the ACK/NACK may be transmitted byusing the same method that is described with reference to Tables 5˜6.More specifically, ACK/NACK state mapping tables of Tables 7˜8 may beconsidered. Tables 7˜8 respectively show a partial state, among thetotal ACK/NACK states, when PCC fallback is being performed. The mappingrelation between the PUCCH resource, which is being used fortransmitting the remaining ACK/NACK state, and the bit value may bearbitrarily defined in the present invention. More specifically, themapping relation between the PUCCH resource, which is being used fortransmitting the remaining ACK/NACK state, and the bit value is don'tcare (irrelevant) in the present invention.

TABLE 7 SCC PCC HARQ- b(0), . . . , HARQ-ACK(0) ACK(1) HARQ-ACK(2)b(M_(bit) − 1) d(0) ACK NACK/DTX NACK/DTX 1 (11) −1 NACK NACK/DTXNACK/DTX 0 (00) +1

Herein, HARQ-ACK(0) represents an ACK/NACK/DTX response for a CW (or TB)of the PCC. HARQ-ACK(1) represents an ACK/NACK/DTX response for CW1 (orTB1) of SCC, and HARQ-ACK(2) represents an ACK/NACK/DTX response for CW2(or TB2) of SCC. The ACK/NACK/DTX response includes ACK, NACK, DTX orNACK/DTX. In the PCC, the NACK includes NACK, DTX or NACK/DTX. d(0)corresponding to the ACK/NACK state is transmitted by using an implicitPUCCH resource, and the implicit PUCCH resource is liked to a PDCCH thatis used for scheduling the CW (or TB) of the PCC (e.g., see Equation 1).PUCCH formats 1a/1b and, more preferably, PUCCH format 1b may be used.

TABLE 8 PCC SCC HARQ- HARQ- HARQ- b(0), . . . , ACK(0) ACK(1) ACK(2)HARQ-ACK(3) b(M_(bit) − 1) d(0) ACK ACK NACK/DTX NACK/DTX 11 −1 ACK NACKNACK/DTX NACK/DTX 10 j NACK ACK NACK/DTX NACK/DTX 01 −j NACK NACKNACK/DTX NACK/DTX 00   1

Herein, HARQ-ACK(0) represents an ACK/NACK/DTX response for CW1 (or TB1)of the PCC, and HARQ-ACK(1) represents an ACK/NACK/DTX response for CW2(or TB2) of the PCC. HARQ-ACK(2) represents an ACK/NACK/DTX response forCW1 (or TB1) of the SCC, and HARQ-ACK(3) represents an ACK/NACK/DTXresponse for CW2 (or TB2) of the SCC. The ACK/NACK/DTX response includesACK, NACK, DTX or NACK/DTX. In the PCC, the NACK includes NACK, DTX orNACK/DTX. d(0) corresponding to the ACK/NACK state is transmitted byusing an implicit PUCCH resource, and the implicit PUCCH resource isliked to a PDCCH that is used for scheduling the CW (or TB) of the PCC(e.g., see Equation 1). PUCCH format 1b may be used.

Conversely, in case of Case 2-2, spatially bundled and/or CC-bundledACK/NACK information respective to multiple ACK/NACKs of multiple CCsmay be transmitted through the SR PUCCH. The SR PUCCH resource means aPUCCH resource (e.g., PUCCH format 1 resource), which is determined by ahigher layer for the SR transmission. Preferably, it may be consideredto transmit the ACK/NACK information for the PCC (in case of a non-MIMOPCC) or the spatially bundled ACK/NACK information for the PCC (in caseof a MIMO PCC) and the bundled ACK/NACK information respective to all ofthe remaining SCCs (secondary DL CCs) by using the SR PUCCH resource.When two CCs (i.e., 1 PCC+1 SCC) are aggregated, the descriptionpresented above may be understood in the sense that ACK/NACK informationthat is spatially bundled for each CC may be transmitted by using the SRPUCCH resource.

Table 9 below shows an exemplary mapping method for bundled ACK/NACKaccording to this embodiment.

TABLE 9 PCC SCC b(0), . . . , Bundled HARQ-ACK(0) Bundled HARQ-ACK(1)b(M_(bit) − 1) d(0) ACK ACK 11 −1 ACK NACK 10 j NACK ACK 01 −j NACK NACK00   1

Herein, bundled HARQ-ACK(0) represents a spatially bundled ACK/NACK/DTXresponse for all CWs (or TBs) of the PCC, and HARQ-ACK(1) represents aspatially bundled ACK/NACK/DTX response for all CWs (or TBs) of the SCC.The NACK includes NACK, DTX or NACK/DTX. In case of this example, ACK isencoded as 1, and NACK is encoded as 0. b(0)b(1) is modulated inaccordance with the table shown above, and the modulation symbol d(0) istransmitted by using the PUCCH resource, which is determined for the SRtransmission. PUCCH format 1b may be used.

Preferably, a combination of the bundled ACK/NACK for the PCC and thebundled ACK/NACK for the SCC (i.e., bundled ACK/NACK state) may bemapped to the SR PUCCH resource for a prevention of a non-conformitybetween the base station and the user equipment during a DL CCreconfiguration section.

FIG. 18 illustrates a bundled ACK/NACK transmitting method according toan embodiment of the present invention.

Referring to FIG. 18, “ACK+NACK/DTX”, which corresponds to a bundledACK/NACK state (hereinafter referred to as a B-A/N state), respective tothe bundled ACK/NACK for all CWs of the PCC (hereinafter referred to asPB-A/N) and to the bundled ACK/NACK for all CWs of the SCC (hereinafterreferred to as SB-A/N) may be mapped to a constellation pointcorresponding to “ACK” of PUCCH format 1a or “ACK+ACK” of PUCCH format1b. Subsequently, “NACK/DTX+NACK/DTX”, which corresponds to a B-A/Nstate, respective to the PB-A/N and the SB-A/N may be mapped to aconstellation point corresponding to “NACK” of PUCCH format 1a or“NACK+NACK” of PUCCH format 1b. Finally, the B-AN state, wherein thePB-A/N and the SB-A/N respectively correspond to ACK+ACK, NACK/DTX+ACK,may be arbitrarily mapped to the remaining two constellation points, towhich the B-A/N states ACK+NACK/DTX, NACK/DTX+NACK/DTX are not mapped.According to this example, during the DL CC reconfiguration section, thebundled ACK/NACK response at least for a case that only the PCC isscheduled may operate normally.

Tables 10˜11 respectively show the exemplary ACK/NACK mapping methodshown in FIG. 18.

TABLE 10 PCC SCC b(0), . . . , Bundled HARQ-ACK(0) Bundled HARQ-ACK(1)b(M_(bit) − 1) d(0) ACK NACK 11 −1 ACK ACK 10 j NACK ACK 01 −j NACK NACK00   1

TABLE 11 PCC SCC b(0), . . . , Bundled HARQ-ACK(0) Bundled HARQ-ACK(1)b(M_(bit) − 1) d(0) ACK NACK 11 −1 NACK ACK 10 j ACK ACK 01 −j NACK NACK00   1

Herein, bundled HARQ-ACK(0) represents a spatially bundled ACK/NACK/DTXresponse for all CWs (or TBs) of the PCC, and HARQ-ACK(1) represents aspatially bundled ACK/NACK/DTX response for all CWs (or TBs) of the SCC.The NACK includes NACK, DTX or NACK/DTX. b(0)b(1) is modulated inaccordance with the table shown above, and the modulation symbol d(0) istransmitted by using the PUCCH resource, which is configured for the SRtransmission. PUCCH format 1b may be used.

Embodiment 2

This embodiment describes a method for efficiently transmitting anACK/NACK and an SR, in a CA-based FDD system, when the system isconfigured so that the user equipment can use the ACK/NACK channelselection method.

In the LTE-A system, in case of the MIMO transmission mode CC, on whicha maximum of 2 CWs can be transmitted for the ACK/NACK channelselection, an ACK/NACK channel selection method either using 2 implicitPUCCH resources, each being linked to a lowest CCE index (n_(CCE)) ofthe PDCCH scheduling the corresponding CC and linked to the next CCEindex (n_(CCE)+1), or using one implicit PUCCH resource and one explicitPUCCH resource, which is in advance allocated by the RRC, may beconsidered. Additionally, in the LTE-A system, in case of the non-MIMOtransmission mode CC, in which a maximum of 1 CW can be transmitted forthe ACK/NACK channel selection, an ACK/NACK channel selection methodusing only one implicit PUCCH #1, which is linked to a lowest CCE index(n_(CCE)) of the PDCCH scheduling the respective CC, may be considered.

Table 12 below shows an exemplary ACK/NACK state-to-symbol (S) mappingfor the ACK/NACK channel selection, in case 2 CCs are configured herein(1 MIMO CC+1 non-MIMO CC). Herein, S represents a BPSK or QPSK symbolbeing mapped/transmitted on an arbitrary constellation within the PUCCHresource, and the number of symbols per PUCCH resource may be varied inaccordance with the overall number of ACK/NACK states.

TABLE 12 MIMO CC PUCCH MIMO CC PUCCH non-MIMO A/N State #1 #2 CC PUCCH#1 State #0 S0 0 0 State #1 S1 0 0 State #2 0 S0 0 State #3 0 S1 0 State#4 0 0 S0 State #5 0 0 S1

At this point, an ACK/NACK state including DTX information respective toa particular CC (i.e., a failure to receive/detect PDCCH that schedulesthe respective CC) may not be mapped/transmitted to/on any positionwithin the implicit PUCCH resource, which is linked to the PDCCH thatschedules the corresponding CC (i.e., which is linked to thecorresponding CC). Since the DTX represents that an implicit PUCCHresource being linked to the corresponding CC is not available, theACK/NACK state cannot be transmitted by using the correspondingresource. More specifically, the implicit PUCCH resource that is linkedto a particular CC and the ACK/NACK state that is mapped to thecorresponding resource may be available/transmitted, only when thereception/detection of the PDCCH that schedules the corresponding CC issuccessfully performed.

Under such conditions, when an ACK/NACK is required to be transmitted ata non-SR subframe, the ACK/NACK state may be transmitted by using theACK/NACK channel selection method without any modification (e.g., seeTables 5˜6). Conversely, when an ACK/NACK is required to be transmittedat an SR subframe, the ACK/NACK and the SR may be transmitted by usingan RS selection between HARQ-ACK PUCCH resources, or by using a PUCCHselection between an ACK/NACK and an SR PUCCH resource. Herein, RSselection represents a method for identifying (or differentiating)negative/positive SRs based upon whether or not the ACK/NACK state onthe first PUCCH resource (i.e., the ACK/NACK that is mapped to a datapart of the first PUCCH resource) is transmitted along with an RS of thefirst PUCCH resource (i.e., an RS having the same CCS/OCC as thecorresponding PUCCH resource or an RS having the same CCS/OCC as thedata part of the corresponding PUCCH resource), or based upon whether ornot the ACK/NACK state on the first PUCCH resource is transmitted alongwith an RS of a second PUCCH resource. And, a PUCCH selection representsa method for identifying (or differentiating) negative/positive SRsbased upon whether or not the ACK/NACK state is transmitted by using thefirst PUCCH resource and the RS of the corresponding resource, or basedupon whether or not the corresponding ACK/NACK state is transmitted byusing the second PUCCH resource and the RS of the correspondingresource. More specifically, with respect to the ACK/NACK states over 2PUCCH resources, which are linked to the MIMO mode CC, thenegative/positive SRs may be identified by applying the RS selectionbetween the corresponding PUCCH resources (Rule 1). And, with respect tothe ACK/NACK states over 1 PUCCH resource, which is linked to thenon-MIMO mode CC, the negative/positive SRs may be identified byapplying the PUCCH selection between the corresponding PUCCH resourceand the SR PUCCH resource (Rule 2).

Meanwhile, when considering the ACK/NACK channel selection using theimplicit PUCCH resource, the ACK/NACK state, which is NACK/DTXrespective to all CWs of all CCs (i.e., all being in an “N/D” state),may not be partially transmitted, due to the characteristics of theimplicit PUCCH resource. For example, for the PCC fallback, only a state(i.e., PCC NACK fallback state), that corresponds to “N” for all CWs ofthe PCC and that corresponds to “N/D” for all CWs of the SCC, may betransmitted though an implicit PUCCH resource, which is linked to thePCC, and the transmission of the state, that corresponds to “D” for allCWs of the PCC and corresponds to “N/D” for all CWs of the SCC, can bedropped (or abandoned). However, in case of the positive SR, since theSR PUCCH resource (i.e., explicit PUCCH resource) can be used, in caseof the positive SR, in order to transmit all states corresponding to“N/D”, the corresponding state may be mapped to the SR PUCCH resource(Rule 3). Preferably, in case the PCC is the MIMO mode, RS selection isnot applied to the positive SR+PCC NACK fallback state, and the positiveSR+PCC NACK fallback state may be replaced with the mapping/transmissionof all “N/D” states on the SR PUCCH resource. By adopting this method,scheduling may be requested to the base station through the positive SRtransmission, even in a situation when available implicit PUCCHresources do not exist, or in a situation when the PDCCH/PDSCH that arereceived by the corresponding user equipment do not exist.

Tables 13˜15 respectively show an exemplary mapping method forperforming SR+ACK/NACK transmission, when 2 CCs are allocated. Table 13shows a case being configured of 1 MIMO CC+1 non-MIMO CC, Table 14 showsa case being configured of 2 MIMO CCs, and Table 15 shows a case beingconfigured of 2 non-MIMO CCs.

In all of the following tables, “nSR” represents a negative SR, and“pSR” represents a negative SR. More specifically, Rule 1 may be appliedfor the ACK/NACK states of the 2 PUCCHs linked to the MIMO CC, and Rule2 may be applied for the ACK/NACK state of the 1 PUCCH linked to thenon-MIMO CC. Additionally, by applying Rule 3, when all ACK/NACK statescorresponding to “N/D” are transmitted by using an SR PUCCH resource, incase of the positive SR, a separate process of PCC NACK fallback statemapping for the positive SR may be omitted. Meanwhile, in case of Table15 (i.e., when multiple non-MIMO CCs exist), all of the ACK/NACK states,which are mapped to the multiple non-MIMO CCs, may each be mapped todifferent constellation points within the SR PUCCH resource for positiveSR transmission.

TABLE 13 non- MIMO CC MIMO CC MIMO PUCCH #1 PUCCH #2 CC Data Data PUCCHSR SR + A/N State part RS part part RS part #1 PUCCH nSR + State#0 S0 10 0 0 0 nSR + State#1 S1 1 0 0 0 0 nSR + State#2 0 0 S0 1 0 0 nSR +State#3 0 0 S1 1 0 0 nSR + State#4 0 0 0 0 S0 0 nSR + State#5 0 0 0 0 S10 pSR + State#0 S0 0 0 1 0 0 pSR + State#1 S1 0 0 1 0 0 pSR + State#2 01 S0 0 0 0 pSR + State#3 0 1 S1 0 0 0 pSR + State#4 0 0 0 0 0 S0 pSR +State#5 0 0 0 0 0 S1 (pSR + all“N/D”) 0 0 0 0 0 (S2)

TABLE 14 MIMO CC MIMO CC MIMO CC #1 #1 #2 MIMO CC #2 PUCCH #1 PUCCH #2PUCCH #1 PUCCH #2 SR SR + A/N State Data RS Data RS Data RS Data RSPUCCH nSR + State#0 S0 1 0 0 0 0 0 0 0 nSR + State#1 S1 1 0 0 0 0 0 0 0nSR + State#2 0 0 S0 1 0 0 0 0 0 nSR + State#3 0 0 S1 1 0 0 0 0 0 nSR +State#4 0 0 0 0 S0 1 0 0 0 nSR + State#5 0 0 0 0 S1 1 0 0 0 nSR +State#6 0 0 0 0 0 0 S0 1 0 nSR + State#7 0 0 0 0 0 0 S1 1 0 pSR +State#0 S0 0 0 1 0 0 0 0 0 pSR + State#1 S1 0 0 1 0 0 0 0 0 pSR +State#2 0 1 S0 0 0 0 0 0 0 pSR + State#3 0 1 S1 0 0 0 0 0 0 pSR +State#4 0 0 0 0 S0 0 0 1 0 pSR + State#5 0 0 0 0 S1 0 0 1 0 pSR +State#6 0 0 0 0 0 1 S0 0 0 pSR + State#7 0 0 0 0 0 1 S1 0 0 pSR +all“N/D” 0 0 0 0 0 0 0 0 S0

TABLE 15 non-MIMO CC non-MIMO CC SR + A/N State #1 PUCCH #1 #2 PUCCH #1SR PUCCH nSR + State#0 S0 0 0 nSR + State#1 S1 0 0 nSR + State#2 0 S0 0nSR + State#3 0 S1 0 pSR + State#0 0 0 S0 pSR + State#1 0 0 S1 pSR +State#2 0 0 S2 pSR + State#3 0 0 S3

Embodiment 3

This embodiment describes a method for efficiently transmitting anACK/NACK and an SR, in a CA-based FDD system, when the system isconfigured so that the user equipment can use the ACK/NACK channelselection method or the multi-bit UCI coding method.

When considering a method for multiplexing the SR and the ACK/NACK byusing both SR resource and ACK/NACK resource, in order to prevent anynon-conformity between the base station and the user equipment at leastwith respect to PCC scheduling within the CC reconfiguration section (orperiod), a mapping that is similar to the above-described PCC fallbackmay be applied in the SR PUCCH resource. More specifically, in case of apositive SR, an A/N state corresponding to “A” or “N/D” for the PCC (oreach CW of the PCC) and an A/N state corresponding “N/D” for each of theremaining SCCS (or each CW of the remaining SCCs) may each bemapped/transmitted through the SR PUCCH resource. Preferably, themapping positions of “A”, “N/D” for the PCC (or each CW of the PCC),which are mapped to each constellation point of the SR PUCCH resourcemay preferably be identical to the mapping positions of “A”, “N”, whichare defined for a single CC allocation/operation (e.g., the mappingpositions of “A”, “N” within PUCCH format 1a, or the mapping positionsof “A”, “N” for each CW within PUCCH format 1b).

FIG. 19 illustrates an exemplary UCI transmitting method according toanother embodiment of the present invention. Referring to FIG. 19, themapping positions of A, N/D for the PCC (or each CW of the PCC), whichare mapped to each constellation point of the SR PUCCH resource maypreferably be identical to the mapping positions of A, N, which aredefined for a single CC allocation/operation (e.g., the mappingpositions of A, N within PUCCH format 1a, or the mapping positions of A,N for each CW within PUCCH format 1b).

Preferably, in case the user equipment receives only the PCC scheduling,i.e., the PDSCH that is scheduled/transmitted through PCC (referring tothe PDSCH or PDCCH (e.g., PDCCH ordering (or commanding) an SPS release)each requiring an ACK/NACK response), the mapping method according tothis embodiment of the present invention may be applied. Morespecifically, in case of a positive SR, an A/N state that corresponds to“A” or “N” for the PCC (or each CW of the PCC) and corresponds to “DTX”for each of the remaining SCCs (or each CW of the remaining SCCs) may bemapped/transmitted to/through the SR PUCCH resource. In other words,this example corresponds to a case that the “N/D” of the PCC is changedto “N”, and the “N/D” of each SCC (CC1, CC2) is changed to “D” in FIG.19.

Additionally, in another example, the application of the mapping methodaccording to the embodiment of the present invention may be limited onlyto the case when the user equipment does not receive even a single PDSCH(referring to the PDSCH or PDCCH (e.g., PDCCH ordering (or commanding)an SPS release) each requiring an ACK/NACK response)) through all CCs.More specifically, in case of a positive SR, an A/N state, thatcorresponds to “DTX” for the PCC (or each CW of the PCC) and correspondsto “DTX” for each of the remaining SCCS (or each CW of the remainingSCCs), may be mapped/transmitted to/through the SR PUCCH resource. Inother words, this example corresponds to a case that the A/N statecorresponding to “A,N/D,N/D” is omitted, and the “N/D” of both the PCCand SCCs (CC1, CC2) are changed to “D” in FIG. 19.

The A/N state mapping within the SR resource may each be applied to acase when FDD ACK/NACK transmission is performed by using an E-PUCCHformat based “multi-bit UCI coding” method or by using a minimum and/orexplicit PUCCH resource based “ACK/NACK channel selection” method.

FIG. 20 illustrates an exemplary UCI transmitting method according toyet another embodiment of the present invention. For simplicity, it willbe assumed that the ACK/NACK is transmitted by using the multi-bit UCIcoding method. The drawing shows an exemplary PUCCH resource allocationprocedure mostly focusing on the ACK/NACK and the SR.

With respect to the ACK/NACK and the SR, four cases may be considered asshown below.

-   -   Case 1: transmit ACK/NACK at a non-SR subframe    -   Case 2: transmit ACK/NACK at an SR subframe, predetermined        condition not satisfied    -   Case 3-1: transmit ACK/NACK at an SR subframe, predetermined        condition satisfied, negative SR    -   Case 3-2: transmit ACK/NACK at an SR subframe, predetermined        condition satisfied, positive SR

Referring to FIG. 20, in case of Case 1, the ACK/NACK is transmitted byusing the multi-bit UCI coding method. More specifically, the ACK/NACKis transmitted by using the E-PUCCH format/resource, which is describedabove with reference to FIG. 12˜13. The HARQ-ACK PUCCH resource for theE-PUCCH format may be explicitly allocated (or assigned) by using theARI. As shown in Table 4, the HARQ-ACK PUCCH resource for the E-PUCCHformat may be indicated by a TPC (Transmit Power Control) field value ofat least one or more SCC PDCCHs.

Cases 2, 3-1 and 3-2 respectively show exemplary cases when the ACK/NACKis to be transmitted at an SR subframe. Case 2 indicates a case when apredetermined condition is not satisfied, and Cases 3-1/3-2 respectivelyindicates a case when a predetermined condition is satisfied.

Herein, the predetermined condition includes a case when the ACK/NACKstate corresponds to “A” or “N/D” for the PCC (or each CW of the PCC)and corresponds to “D” for the remaining SCCs (or each CW of theremaining SCCs). In other words, the predetermined condition includes acase when one PDSCH or one SPS release PDCCH is detected only on thePCC. When the predetermined condition is not satisfied (i.e., Case 2),the user equipment may perform joint coding on the ACK/NACK informationand the SR information (e.g., 1-bit for indicating negative/positiveSR)(e.g., negative SR: 0, positive SR: 1) and may then transmit thejoint-coded information. The joint-coded ACK/NACK+SR may be transmittedby using the E-PUCCH format/resource. When the predetermined conditionis satisfied, and when the SR corresponds to a negative SR (i.e., Case3-1), the user equipment may transmit the ACK/NACK by using PUCCHformats 1a/1b and the implicit PUCCH resource of the conventional LTEsystem. Alternatively, when the predetermined condition is satisfied,and when the SR corresponds to a positive SR (i.e., Case 3-2), the userequipment may transmit the ACK/NACK by using the PUCCH resource, whichis configured for the SR transmission. In this case, the ACK/NACK may betransmitted by using the PUCCH formats 1a/1b.

Embodiment 4

The conventional LTE TDD system uses an ACK/NACK bundling method and anACK/NACK channel selection method in order to transmit the ACK/NACK.Meanwhile, when the ACK/NACK is transmitted at an SR subframe and whenthe respective SR corresponds to a negative SR, the user equipmenttransmits the ACK/NACK by using a configured ACK/NACK transmissionmethod (i.e., ACK/NACK bundling or ACK/NACK channel selection) andHARQ-ACK PUCCH resources. Conversely, when the ACK/NACK is transmittedat the SR subframe and when the respective SR corresponds to a positiveSR, the user equipment maps a number of ACKs (i.e., ACK counter) for thePDSCH, which is received through multiple DL subframes, to constellationpoints [b(0), b(1)] within the SR resource, thereby transmitting theACKs.

Table 16 below shows a relation between the number of ACKs and b(0),b(1) within the conventional LTE TDD.

TABLE 16 Number of ACK among multiple (U_(DAI) + N_(SPS)) ACK/NACKresponses b(0), b(1) 0 or None (UE detect at least one DL assignment ismissed) 0, 0 1 1, 1 2 1, 0 3 0, 1 4 1, 1 5 1, 0 6 0, 1 7 1, 1 8 1, 0 90, 1

Herein, U_(DAI) represents a total number of PDCCH(s) having allocatedPDSCH transmission and PDCCHs indicating downlink SPS release, which aredetected by the user equipment from subframe(s) n−k (kεK). N_(SPS)indicates a number of PDSCH transmissions without corresponding PDCCHwithin the subframe(s) n−k (kεK). Subframe n corresponds to the SRsubframe.

K is given by a UL-DL configuration. And, Table 17 below shows K: {k₀,k₁, . . . k_(M-1)}, which is defined in the conventional LTE TDD.

TABLE 17 UL-DL Subframe n Configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4— — 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, 4,6 — — 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, 4, 7 —— — — — — 5 — — 13, 12, 9, 8, 7, 5, 4, 11, 6 — — — — — — — 6 — — 7 7 5 —— 7 7 —

Hereinafter, a method enabling the user equipment to efficientlytransmit the ACK/NACK and the SR in the CA based TDD system will bedescribed. In the TDD system, when multiple CCs are aggregated, it maybe considered to transmit multiple ACK/NACK information/signalsrespective to multiple PDSCHs, which are received through multiple DLsubframes and multiple CCs, through a specific CC (i.e., A/N CC) at a ULsubframe, which corresponds to the respective multiple DL subframes.

Two different methods for the ACK/NACK transmission may be considered asdescribed below.

-   -   Full ACK/NACK method: a plurality of ACK/NACKs corresponding to        a maximum number of CWs, which can be transmitted through all        CCs allocated to the user equipment and multiple DL subframes        (i.e., SF n−k (kεK)), may be transmitted.    -   Bundled ACK/NACK method: a total number of transmitted ACK/NACK        bits may be reduced by applying at least one of CW bundling, CC        bundling, and subframe (SF) bundling, thereby being transmitted.

CW bundling refers to applying ACK/NACK bundling for each CC withrespect to each DL SF. CC bundling refers to applying ACK/NACK bundlingto all CCs or a portion of the CCs with respect to each DL SF. SFbundling refers to applying ACK/NACK bundling to each CC with respect toall DL SFs or a portion of the DL SFs. ACK/NACK bundling refers to alogical AND operation process to multiple ACK/NACK responses. Meanwhile,in case of SF bundling, an “ACK-counter” method, which notifies a totalnumber of ACKs (or a number of some of the ACKs) for each CC withrespect to all PDSCHs or DL grant PDCCHs received for each CC, may beadditionally considered. In this embodiment, the ACK counter may bedefined as described (or defined) in Table 16, or may be defined asdescribed below. The difference between the definition shown in Table 16and the definition described below is that the number of ACKs is countedas 0, when at least one NACK exists.

ACK counter: corresponds to a method for notifying a total number ofACKs (or a partial number of ACKs), which are received for all PDSCHs.More specifically, the number of ACKs is notified by the user equipment,only when all of the received PDSCHs correspond to ACK, and when no DTXis detected. And, when the user equipment detects the DTX, or when atleast one NACK exists for the received PDSCH, the number of ACKs may benotified as 0 (processed as DTX or NACK).

Meanwhile, an ACK/NACK payload, which is generated by using the fullACK/NACK method or the bundled ACK/NACK method, may be transmitted byusing a “multi-bit UCI coding” or “ACK/NACK channel selection” basedACK/NACK transmission method. The “multi-bit UCI coding” or “ACK/NACKchannel selection” may be adaptively applied based upon an ACK/NACKpayload size.

Preferably, for a positive SR in the SR subframe, and when only the PCCscheduling PDSCH(s) (i.e., PDSCH(s) being scheduled/transmitted throughthe PCC) is/are received in the multiple DL subframes corresponding tothe SR subframe, the user equipment may map/transmit the ACK/NACK on theSR resource by applying an ACK counter or SF bundling method for onlythe PDSCH of the PCC. In the SR subframe, for a negative SR, the userequipment may transmit the ACK/NACK by using “multi-bit UCI coding” or“ACK/NACK channel selection” and HARQ-ACK PUCCH resources.

Preferably, for a positive SR in the SR subframe, and when not a singlePDSCH is received through all CCs within the multiple DL subframescorresponding to the SR subframe, the user equipment may map/transmitthe ACK/NACK on the SR resource by applying an ACK counter or SFbundling method for only the PDSCH of the PCC. In the SR subframe, for anegative SR, the user equipment may transmit the ACK/NACK by using“multi-bit UCI coding” or “ACK/NACK channel selection” and HARQ-ACKPUCCH resources.

Preferably, when multi-bit UCI coding is applied for TDD ACK/NACKtransmission, for a positive SR in the SR subframe, and when theACK/NACK(s) for the PDSCH, which is received through all secondary CC(s)excluding the PCC, corresponds to NACK or DTX, the user equipment maymap/transmit ACK counter information respective to the multiple DLsubframes of the PCC on the SR resource. In the SR subframe, for anegative SR, the user equipment may transmit the ACK/NACK by using“multi-bit UCI coding” or “ACK/NACK channel selection” and HARQ-ACKPUCCH resources.

Preferably, when ACK counter based ACK/NACK channel selection is appliedfor TDD ACK/NACK transmission and when the SR subframe corresponds to apositive SR, the user equipment may always map/transmit the ACK counterinformation respective to the multiple DL subframes of the PCC,regardless of whether or not a PDSCH, which is scheduled to thesecondary CC(s), is received (and regardless of the respective ACK/NACKresponse). In the SR subframe, for a negative SR, the user equipment maytransmit the ACK/NACK by using “multi-bit UCI coding” or “ACK/NACKchannel selection” and HARQ-ACK PUCCH resources.

Additionally, in a TDD situation, a case when a DAI (Downlink AssignmentIndex) is independently operated for each CC may be considered. Morespecifically, a case when DAI signaling is performed only to the PDSCHof the corresponding CC through a PDCCH. Preferably, the DAI maycorrespond to a DAI-counter (e.g., a parameter notifying a schedulingorder of the PDSCH, which is scheduled based upon a pre-decided order(e.g., DL subframe order)). In case of using the DAI-counter, the userequipment may perform operations of 1) notifying the number of ACKs tothe base station, only when the number of received DAIs is equal to thetotal number of ACKs, to the base station or 2) notifying a number ofACKs corresponding to the DAI-counter value, which is consecutively (orcontinuously) increased starting from an initial DAI-counter value (orstarting from the respective PDSCH), to the base station. The DAI mayhave the initial values of 0 or 1.

Preferably, for a positive SR in the SR subframe, and when the userequipment receives a PDSCH corresponding to a PDCCH with an initial DAIvalue, a single PDCCH indicating SPS release, and/or a single SPS PDSCH(i.e., PDSCH without corresponding PDCCH) only through the PCC, the userequipment may map/transmit ACK/NACK information (e.g., ACK counterinformation) on the PDSCH corresponding to the initial DAI or the PDCCHand/or the SPS PDSCH of the PCC. Additionally, for a positive SR in theSR subframe, when not a single PDSCH or PDCCH is received through allCCs within the multiple DL subframes corresponding to the SR subframe(i.e., when no PDSCH or PDCCH transmission is performed with respect tothe user equipment), the user equipment may map/transmit a bit value (ormodulation value) corresponding to number of ACKs=0 on the SR resource.In the SR subframe, for a negative SR, the user equipment may transmitthe ACK/NACK by using “multi-bit UCI coding” or “ACK/NACK channelselection” and HARQ-ACK PUCCH resources.

FIG. 21 illustrates an exemplary UCI transmitting method according toyet another embodiment of the present invention. For simplicity, it willbe assumed that the ACK/NACK is transmitted by using the multi-bit UCIcoding method. The drawing shows an exemplary PUCCH resource allocationprocedure mostly focusing on the ACK/NACK and the SR.

With respect to the ACK/NACK and the SR, four cases may be considered asshown below.

-   -   Case 1: transmit ACK/NACK at a non-SR subframe    -   Case 2: transmit ACK/NACK at an SR subframe, predetermined        condition not satisfied    -   Case 3-1: transmit ACK/NACK at an SR subframe, predetermined        condition satisfied, negative SR    -   Case 3-2: transmit ACK/NACK at an SR subframe, predetermined        condition satisfied, positive SR

Referring to FIG. 21, in case of Case 1, the ACK/NACK is transmitted byusing the multi-bit UCI coding method. More specifically, the ACK/NACKis transmitted by using the E-PUCCH format/resource, which is describedabove with reference to FIG. 12˜13. The PUCCH resource for the E-PUCCHformat may be explicitly allocated (or assigned). As shown in Table 4,the PUCCH resource may be indicated by using an ARI, which is signaledthrough a specific PDCCH. Herein, the specific PDCCH may correspond toany one of the PDCCHs excluding a PDCCH having an initial DAI value andscheduling the PCell.

Cases 2, 3-1 and 3-2 respectively show exemplary cases when the ACK/NACKis to be transmitted at the SR subframe. Case 2 indicates a case when apredetermined condition is not satisfied, and Cases 3-1/3-2 respectivelyindicates a case when a predetermined condition is satisfied.

Herein, the predetermined condition includes at least one of cases(1)˜(4) described below.

(1) a single PDSCH transmission only on the PCell indicated by detectionof a PDCCH having a Downlink Assignment Index (DAI) initial value ispresent. The initial DAI value may be 0 or 1.

(2) a single PDCCH transmission only on the PCell that has the DAIinitial value and indicates a downlink Semi-Persistent Scheduling (SPS)release is present. The initial DAI value may be 0 or 1.

(3) a single PDSCH transmission only on the PCell where there is not acorresponding PDCCH.

When the predetermined condition is not satisfied (i.e., Case 2), theuser equipment may perform joint coding on the ACK/NACK information andthe SR information (e.g., negative/positive SR indicating 1-bit)(e.g.,negative SR: 0, positive SR: 1) and may then transmit the joint-codedinformation. The joint-coded ACK/NACK+SR may be transmitted by using theE-PUCCH format/resource. The HARQ-ACK PUCCH resource for the E-PUCCHformat may be explicitly allocated by using the ARI. For example, theHARQ-ACK PUCCH resource for the E-PUCCH format may be indicated by thevalue of a TPC (Transmit Power Control) field of at least one or moreSCell PDCCH and/or at least one or more Pcell PDCCHs that do notcorrespond to the initial DAI value.

When the predetermined condition is satisfied, and when the SRcorresponds to a negative SR (i.e., Case 3-1), the user equipment maytransmit the ACK/NACK by using PUCCH formats 1a/1b and the implicitPUCCH resource of the conventional LTE system. An implicit PUCCHresource may be used for cases (1)(2), and an explicit PUCCH resourcemay be used for case (3). For example, the ACK/NACK may be transmittedin accordance with the ACK/NACK channel selection method using PUCCHformat 1b. Alternatively, when the predetermined condition is satisfied,and when the SR corresponds to a positive SR (i.e., Case 3-2), the userequipment may transmit the ACK/NACK by using the PUCCH resource, whichis configured for the SR transmission. In this case, the ACK/NACK may betransmitted by using the PUCCH formats 1b.

FIG. 22 illustrates an exemplary base station and an exemplary userequipment that can be applied to the embodiment of the presentinvention. When a relay is included in a wireless (or radio)communication system, in a Backhaul link, communication is realizedbetween the base station and the relay. And, in an access link,communication is realized between the relay and the user equipment.Therefore, depending upon the respective situation, the terms basestation and user equipment may be adequately replaced by the term relay.

Referring to FIG. 22, a wireless communication system includes a basestation (BS, 110) and a user equipment (UE, 120). The base station (110)includes a processor (112), a memory (114), and a Radio Frequency (RF)unit (116). The processor (112) may be configured to realize theprocedures and/or methods proposed in the present invention. The memory(114) is connected to the processor (112) and stores diverse informationrelated to the operations of the processor (112). The RF unit (116) isconnected to the processor (112) and transmits and/or receives radiosignals. The user equipment (120) includes a processor (122), a memory(124), and an RF unit (126). The processor (122) may be configured torealize the procedures and/or methods proposed in the present invention.The memory (124) is connected to the processor (122) and stores diverseinformation related to the operations of the processor (122). The RFunit (126) is connected to the processor (122) and transmits and/orreceives radio signals. The base station (110) and/or the user equipment(120) may have a single antenna or multiple antennae.

The embodiments described above correspond to predetermined combinationsof elements and features and characteristics of the present invention.Moreover, unless mentioned otherwise, the characteristics of the presentinvention may be considered as optional features of the presentinvention. Herein, each element or characteristic of the presentinvention may also be operated or performed without being combined withother elements or characteristics of the present invention.Alternatively, the embodiment of the present invention may be realizedby combining some of the elements and/or characteristics of the presentinvention. Additionally, the order of operations described according tothe embodiment of the present invention may be varied. Furthermore, partof the configuration or characteristics of any one specific embodimentof the present invention may also be included in (or shared by) anotherembodiment of the present invention, or part of the configuration orcharacteristics of any one embodiment of the present invention mayreplace the respective configuration or characteristics of anotherembodiment of the present invention. Claims that do not have anyexplicit citations within the scope of the claims of the presentinvention may either be combined to configure another embodiment of thepresent invention, or new claims may be added during the amendment ofthe present invention after the filing for the patent application of thepresent invention.

In this document, the embodiments of the present invention will bedescribed by mainly focusing on the data transmission and receptionrelation between the base station and the terminal (or user equipment).Occasionally, in the description of the present invention, particularoperations of the present invention that are described as beingperformed by the base station may also be performed by an upper node ofthe base station. More specifically, in a network consisting of multiplenetwork nodes including the base station, it is apparent that diverseoperations that are performed in order to communicate with the terminalmay be performed by the base station or b network nodes other than thebase station. Herein, the term Base Station may be replaced by otherterms, such as fixed station, Node B, eNode B (eNB), Access Point (AP),and so on. And, the term User Terminal may be replaced by other terms,such as UE (User Equipment), MS (Mobile Station), MSS (Mobile SubscriberStation), and so on.

The above-described embodiments of the present invention may beimplemented by using a variety of methods, e.g., being realized in theform of hardware, firmware, or software, or in a combination ofhardware, firmware, and/or software. In case of implementing theembodiments of the present invention in the form of hardware, the methodaccording to the embodiments of the present invention may be implementedby using at least one of ASICs (application specific integratedcircuits), DSPs (digital signal processors), DSPDs (digital signalprocessing devices), PLDs (programmable logic devices), FPGAs (fieldprogrammable gate arrays), processors, controllers, micro controllers,micro processors, and so on.

In case of implementing the embodiments of the present invention in theform of firmware or software, the method according to the embodiments ofthe present invention may be implemented in the form of a module,procedure, or function performing the above-described functions oroperations. A software code may be stored in a memory unit and driven bya processor. Herein, the memory unit may be located inside or outside ofthe processor, and the memory unit may transmit and receive data to andfrom the processor by using a wide range of methods that have alreadybeen disclosed.

It will be apparent to anyone skilled in the art that the presentinvention can be realized in another concrete configuration (orformation) without deviating from the scope and spirit of thecharacteristics of the present invention. Therefore, in all aspect, thedetailed description of present invention is intended to be understoodand interpreted as an exemplary embodiment of the present inventionwithout limitation. The scope of the present invention shall be decidedbased upon a reasonable interpretation of the appended claims of thepresent invention and shall come within the scope of the appended claimsand their equivalents.

The present invention may be used in wireless communication devices,such as user equipments, relays, base stations, and so on.

What is claimed is:
 1. A method for transmitting uplink control information at a communication apparatus configured with a plurality of cells including a Primary Cell (PCell) and a Secondary Cell (SCell) in a wireless communication system operating in a Time Division Duplex (TDD) mode, the method comprising: receiving, by the communication apparatus, one or more downlink signals requiring Hybrid Automatic Repeat reQuest Acknowledgement (HARQ-ACK) feedback in a set of subframes; and transmitting, by the communication apparatus, reception response information about the one or more downlink signals through a Physical Uplink Control CHannel (PUCCH) on a subframe configured for Scheduling Request (SR) transmission, wherein when a predetermined condition is not satisfied, the reception response information and SR information are multiplexed and transmitted using a first HARQ-ACK PUCCH resource, wherein when the predetermined condition is satisfied, for a positive SR, the reception response information includes information about an ACK count for the one or more downlink signals and is transmitted using a SR PUCCH resource, and the ACK count is set to 0 when the reception response information about the one or more downlink signals includes Discontinuous Transmission (DTX), and wherein the predetermined condition includes at least one of detecting a single downlink signal corresponding to a Downlink Assignment Index (DAI) initial value only on the PCell in the set of subframes, and detecting a single downlink signal scheduled by a Semi-Persistent Scheduling (SPS) only on the PCell in the set of subframes.
 2. The method of claim 1, wherein the DAI initial value is
 1. 3. The method of claim 1, wherein 1-bit information indicating a positive/negative SR is added to the reception response information when the predetermined condition is not satisfied.
 4. The method of claim 1, wherein the first HARQ-ACK PUCCH resource is assigned by a Radio Resource Control (RRC) signal.
 5. The method of claim 1, wherein when the predetermined condition is satisfied, for a negative SR, the reception response information is transmitted using a second HARQ-ACK PUCCH resource.
 6. A communication apparatus configured to transmit uplink control information in a situation that a plurality of cells including a PCell and an SCell are configured in a wireless communication system operating in a Time Division Duplex (TDD) mode, the communication apparatus comprising: a Radio Frequency (RF) unit; and a processor configured to: receive one or more downlink signals requiring Hybrid Automatic Repeat reQuest Acknowledgement (HARQ-ACK) feedback in a set of subframes, and transmit reception response information about the one or more downlink signals through a Physical Uplink Control CHannel (PUCCH) on a subframe configured for Scheduling Request (SR) transmission, wherein when a predetermined condition is not satisfied, the reception response information and SR information are multiplexed and transmitted using a first HARQ-ACK PUCCH resource, wherein when the predetermined condition is satisfied, for a positive SR, the reception response information includes information about an ACK count for the one or more downlink signals and is transmitted using a SR PUCCH resource, and the ACK count is set to 0 when the reception response information about the one or more downlink signals includes Discontinuous Transmission (DTX), and wherein the predetermined condition includes at least one of: detecting a single downlink signal corresponding to a Downlink Assignment Index (DAI) initial value only on the PCell in the set of subframes, and detecting a single downlink signal scheduled by a Semi-Persistent Scheduling (SPS) only on the PCell in the set of subframes.
 7. The communication apparatus of claim 6, wherein the DAI initial value is
 1. 8. The communication apparatus of claim 6, wherein 1-bit information indicating a positive/negative SR is added to the reception response information when the predetermined condition is not satisfied.
 9. The communication apparatus of claim 6, wherein the first HARQ-ACK PUCCH resource is assigned by a Radio Resource Control (RRC) signal.
 10. The communication apparatus of claim 6, wherein when the predetermined condition is satisfied, for a negative SR, the reception response information is transmitted using a second HARQ-ACK PUCCH resource. 